U.S. concerns over Saudi Arabia Iran dnt labott lead   _00021123.jpg
Reuters
U.S. concerns over Saudi Arabia Iran dnt labott lead _00021123.jpg
Now playing
02:37
U.S. concerned about growing Iran, Saudi tensions
Saudi Crown Prince Mohammed bin Salman attends the Future Investment Initiative (FII) conference in Riyadh, on October 24, 2017.
The Crown Prince pledged a "moderate, open" Saudi Arabia, breaking with ultra-conservative clerics in favour of an image catering to foreign investors and Saudi youth.  "We are returning to what we were before -- a country of moderate Islam that is open to all religions and to the world," he said at the economic forum in Riyadh.
FAYEZ NURELDINE/AFP/Getty Images
Saudi Crown Prince Mohammed bin Salman attends the Future Investment Initiative (FII) conference in Riyadh, on October 24, 2017. The Crown Prince pledged a "moderate, open" Saudi Arabia, breaking with ultra-conservative clerics in favour of an image catering to foreign investors and Saudi youth. "We are returning to what we were before -- a country of moderate Islam that is open to all religions and to the world," he said at the economic forum in Riyadh.
Now playing
02:53
The man in charge of Saudi Arabia
A general manager of Alarab TV, Jamal Khashoggi, looks on during a press conference in the Bahraini capital Manama, on December 15, 2014. The  pan-Arab satellite news broadcaster owned by billionaire Saudi businessman Alwaleed bin Talal will go on air February 1, promising to "break the mould" in a crowded field.AFP PHOTO/ MOHAMMED AL-SHAIKH        (Photo credit should read MOHAMMED AL-SHAIKH/AFP/Getty Images)
MOHAMMED AL-SHAIKH/AFP/Getty Images
A general manager of Alarab TV, Jamal Khashoggi, looks on during a press conference in the Bahraini capital Manama, on December 15, 2014. The pan-Arab satellite news broadcaster owned by billionaire Saudi businessman Alwaleed bin Talal will go on air February 1, promising to "break the mould" in a crowded field.AFP PHOTO/ MOHAMMED AL-SHAIKH (Photo credit should read MOHAMMED AL-SHAIKH/AFP/Getty Images)
Now playing
00:42
Turkish official: Khashoggi's body was cut into pieces
CNN
Now playing
03:02
Pompeo speaks following Saudi Arabia trip
FILE - In this Jan. 29, 2011, file photo, Saudi Arabian journalist Jamal Khashoggi speaks on his cellphone at the World Economic Forum in Davos, Switzerland. The Washington Post said Wednesday, Oct. 3, 2018, it was concerned for the safety of Khashoggi, a columnist for the newspaper, after he apparently went missing after going to the Saudi Consulate in Istanbul. (AP Photo/Virginia Mayo, File)
Virginia Mayo/AP
FILE - In this Jan. 29, 2011, file photo, Saudi Arabian journalist Jamal Khashoggi speaks on his cellphone at the World Economic Forum in Davos, Switzerland. The Washington Post said Wednesday, Oct. 3, 2018, it was concerned for the safety of Khashoggi, a columnist for the newspaper, after he apparently went missing after going to the Saudi Consulate in Istanbul. (AP Photo/Virginia Mayo, File)
Now playing
03:36
Questions linger after journalist disappears
31st August 1945:  Five sons of King Abdul Aziz Ibn Saud of Saudi Arabia board a plane at Herne Airport in Hampshire. They are the Amir Faisal (later King Faisal), Amir Mohammed, Amir Fahd (later King Fahd), Amir Abdullah Al Faisal and Amir Nawaf. On the left is the Saudi Ambassador in London.  (Photo by William Vanderson/Fox Photos/Getty Images)
William Vanderson/Hulton Royals Collection/Getty Images
31st August 1945: Five sons of King Abdul Aziz Ibn Saud of Saudi Arabia board a plane at Herne Airport in Hampshire. They are the Amir Faisal (later King Faisal), Amir Mohammed, Amir Fahd (later King Fahd), Amir Abdullah Al Faisal and Amir Nawaf. On the left is the Saudi Ambassador in London. (Photo by William Vanderson/Fox Photos/Getty Images)
Now playing
01:13
Saudi Arabia's royal family: What to know
CNN
Now playing
02:45
Saudi women drivers get behind the wheel
Luke Rotzler/CNN
Now playing
01:43
'I'm a prisoner and my crime is that I'm a Saudi woman'
A picture taken on November 5, 2017 in Riyadh shows a general view of the closed Ritz Karlton hotel in Riyadh.
A day earlier Saudi Arabia arrested 11 princes, including a prominent billioniare, and dozens of current and former ministers, reports said, in a sweeping crackdown as the kingdom's young crown prince Mohammed bin Salman consoliates power. / AFP PHOTO / FAYEZ NURELDINE        (Photo credit should read FAYEZ NURELDINE/AFP/Getty Images)
FAYEZ NURELDINE/AFP/AFP/Getty Images
A picture taken on November 5, 2017 in Riyadh shows a general view of the closed Ritz Karlton hotel in Riyadh. A day earlier Saudi Arabia arrested 11 princes, including a prominent billioniare, and dozens of current and former ministers, reports said, in a sweeping crackdown as the kingdom's young crown prince Mohammed bin Salman consoliates power. / AFP PHOTO / FAYEZ NURELDINE (Photo credit should read FAYEZ NURELDINE/AFP/Getty Images)
Now playing
02:10
Saudi Arabia arrests 11 princes after protest
Getty Images
Now playing
02:15
Why are Iran and Saudi Arabia so at odds?
Myrkott/Masmeer
Now playing
02:39
Cartoonist draws lines in Saudi culture
HANGZHOU, CHINA - SEPTEMBER 04:  Saudi Arabia Deputy Crown Prince Mohammed bin Salman attends the G20 opening ceremony at the Hangzhou International Expo Center on September 4, 2016 in Hangzhou, China. World leaders are gathering for the 11th G20 Summit from September 4-5. (Photo by Nicolas Asfouri - Pool/Getty Images)
Nicolas Asfouri/Pool/Getty Images
HANGZHOU, CHINA - SEPTEMBER 04: Saudi Arabia Deputy Crown Prince Mohammed bin Salman attends the G20 opening ceremony at the Hangzhou International Expo Center on September 4, 2016 in Hangzhou, China. World leaders are gathering for the 11th G20 Summit from September 4-5. (Photo by Nicolas Asfouri - Pool/Getty Images)
Now playing
01:28
Saudi Arabia: What's going on?
saudi arabia power grab robertson pkg_00022512.jpg
saudi arabia power grab robertson pkg_00022512.jpg
Now playing
02:27
Crown Prince leads anti-corruption sweep
Saudi princes and top offiicials arrested for corruption Anderson looklive_00004407.jpg
Saudi princes and top offiicials arrested for corruption Anderson looklive_00004407.jpg
Now playing
02:12
Saudi Arabia princes arrested in corruption case
Saudi Crown Prince Mohammed bin Salman attends the Future Investment Initiative (FII) conference in Riyadh, on October 24, 2017.
The Crown Prince pledged a "moderate, open" Saudi Arabia, breaking with ultra-conservative clerics in favour of an image catering to foreign investors and Saudi youth.  "We are returning to what we were before -- a country of moderate Islam that is open to all religions and to the world," he said at the economic forum in Riyadh.
 / AFP PHOTO / FAYEZ NURELDINE        (Photo credit should read FAYEZ NURELDINE/AFP/Getty Images)
FAYEZ NURELDINE/AFP/AFP/Getty Images
Saudi Crown Prince Mohammed bin Salman attends the Future Investment Initiative (FII) conference in Riyadh, on October 24, 2017. The Crown Prince pledged a "moderate, open" Saudi Arabia, breaking with ultra-conservative clerics in favour of an image catering to foreign investors and Saudi youth. "We are returning to what we were before -- a country of moderate Islam that is open to all religions and to the world," he said at the economic forum in Riyadh. / AFP PHOTO / FAYEZ NURELDINE (Photo credit should read FAYEZ NURELDINE/AFP/Getty Images)
Now playing
01:30
The young prince in charge of Saudi Arabia (2017)
Now playing
02:19
Spokeswoman defends progress in Saudi Arabia

Story highlights

NEW: Saudi Arabia accuses Iranian authorities of failing in their duties to protect the Saudi embassy

Iran says it's committed to protecting foreign missions

After Saudi Arabia cuts ties with Iran, Bahrain and Sudan follow suit

CNN —  

The fallout of Saudi Arabia’s execution of a Shiite cleric is spreading beyond a spat between the Saudis and Iranians, as other Middle East nations chose sides Monday and world powers Russia and China weighed in.

Relations between Saudi Arabia and Iran – two Middle Eastern powerhouses – quickly deteriorated following Riyadh’s execution of Shiite cleric Nimr al-Nimr Saturday.

Hours after the death sentence was carried out, protesters in Shiite-majority Iran attacked the Saudi Embassy in Tehran. The Saudis cut diplomatic relations with Iran over the attack on its embassy.

Saudi-Iran feud jeopardizes U.S. efforts on ISIS, Syria

Officials from both countries defended their positions Monday and showed no sign of backing down.

Saudi Arabia suspended all flights to and from Iran. It also sent a letter to the U.N. Security Council accusing Iranian authorities of failing in their duties to protect the Saudi embassy.

Jaberi Ansari, a spokesman for Iran’s foreign ministry, said his country is committed to protecting diplomatic missions and reiterated that no Saudi diplomats were harmed – or even present – during the attack.

He accused Saudi Arabia of “looking for some excuses to pursue its own unwise policies to further tension in the region.”

Meanwhile, some nations picked sides while others called for calm.

Saudi execution of Shia cleric threatens to deepen regional sectarian crisis

Here’s the latest on where things stand:

Picking sides

Bahrain announced Monday that it was severing diplomatic ties with Iran, citing Tehran’s “blatant and dangerous interference” in Bahrain and other Arab countries.

The United Arab Emirates said it was “downgrading” its diplomatic relations with Iran. The UAE recalled its ambassador in Tehran and said it would also reduce the number of diplomats stationed in Iran, according to state news agency WAM. A government statement said the UAE “has taken this exceptional step in light of Iran’s ongoing interference in internal (Gulf Cooperation Council) and Arab affairs that has recently reached unprecedented levels.”

The diplomatic row spread to Africa, where Sudan – a majority Sunni Muslim country – expelled the Iranian ambassador and the entire Iranian diplomatic mission in the country. Sudan also recalled its ambassador from Iran.

The Saudi government announced the Sudanese move, saying Sudan acted because of “the Iranian interference in the region through a sectarian approach.”

Russia and China, two of the biggest geopolitical players in the hemisphere, released statements calling for restraint between Iran and Saudi Arabia.

“Moscow is concerned about escalation of the situation in the Middle East with participation of the key regional players,” the Russian foreign ministry said Monday. Russia called on the Saudis and Iranians to “show restraint and to avoid any steps that might escalate the situation and raise tensions including interreligious ones.”

China’s foreign ministry said it is paying close attention to the events and hopes “all parties can remain calm and restrained, use dialogue and negotiations to properly resolve differences, and work together to safeguard the region’s peace and stability.”

Saudi anti-terror coalition challenges U.S. role in Middle East

Could the diplomatic war of words boil over?

It had – even before Saudi Arabia announced its decision to cut ties with Iran, said Fawaz Gerges, chair of contemporary Middle Eastern studies at the London School of Economics.

“Their conflict is playing out on Arab streets big time,” he said.

Already the two nations were on opposite sides of conflicts in Syria, Iraq, Yemen, Bahrain and Lebanon. Now, he said, the question is how much worse things might get.

“The situation is extremely volatile between the two most powerful states in the Gulf, Sunni-dominated Saudi Arabia and Shiite-dominated Iran. You have a war of words. You have war by proxies … This really could get very ugly and dangerous in the next few weeks and next few months,” Gerges said.

It’s possible a more direct military conflict between Saudi Arabia and Iran could erupt, said retired Lt. Gen. Mark Hertling, a CNN military analyst.

“That’s the key issue,” he said. “This is spiraling very quickly.”

Read more; Saudi execution of Shia cleric threatens to deepen regional sectarian crisis

Why are there tensions between Iran and Saudi Arabia?

It’s nothing new that the two countries aren’t seeing eye to eye.

“Iran and Saudi Arabia are neither natural allies nor natural enemies, but natural rivals who have long competed as major oil producers and self-proclaimed defenders of Shia and Sunni Islam, respectively,” University of South Florida Professor Mohsen M. Milani wrote in an analysis for CNN in 2011.

Both Saudi Arabia and Iran are painting themselves as victims as tensions between them escalate, Gerges said.

“What you have is not only a clash of narratives, you have basically a huge divide, a war by proxy, a cold war taking place between Saudi Arabia and Iran,” he said. “It’s a war about geopolitics. It’s about power. It’s about influence.”

So why are things getting worse now?

The latest flashpoint emerged after Saudi Arabia executed dissident Shiite cleric Nimr al-Nimr and dozens of others over the weekend.

It wasn’t long before protesters attacked the Saudi embassy in Tehran, hurling Molotov cocktails and cheering as the building caught fire. Iran’s Supreme Leader Ayatollah Ali Khamenei called for divine revenge against Saudi Arabia.

“It was almost inevitable that this (the severing of diplomatic relations) would follow, especially since the response from Iran, completely expectedly, was full of rage, and Iran’s supreme leader essentially summoned the wrath of God against Saudi Arabia,” said Bobby Ghosh, a CNN global affairs analyst and managing editor of Quartz.

But analysts say looking within Iran and Saudi Arabia gives a greater understanding of why both countries have an interest in fueling the rivalry.

“There are domestic reasons for both of these countries right now to refuse to pull punches against each other,” said Ian Bremmer, president of the Eurasia Group consulting firm.

Saudi Arabia, he said, is dealing with plummeting oil prices and an internal succession battle over who will next take the throne.

Iran, he said, needs a way to block reformists and Western advances in light of the recent nuclear deal. For both sides, he said, nationalist behavior can score points at home.

“That,” Bremmer said, “makes this an incredibly dangerous conflict.”

What can we expect to see in the coming days?

Don’t expect the heated rhetoric to die down any time soon, analysts said.

“This is Saudi Arabia saying, ‘The gloves are off,’” Ghosh said.

Gerges said that could ripple across the region.

“We were hoping that a diplomatic solution could be found to the Syrian crisis in the next few months. Forget about it,” he said.

“We were hoping for a diplomatic solution in Yemen. Forget about it. … Here, you have the two most powerful Islamic states in the heart of the Middle East now basically waging a direct confrontation, as opposed to an indirect war by proxy, so … we should be really alarmed at the escalation of the confrontation.”

CORRECTION: A previous version of this story incorrectly identified the country that executed Shiite cleric Nimr al-Nimr. Saudi Arabia executed him.

CNN’s Merieme Arif, Kevin Wang, Mohammed Tawfeeq, Alla Eshchenko, Jonathan Mann, Jim Sciutto and Yousuf Basil contributed to this report.