This AFPTV screen grab from a video made on September 14, 2019, shows smoke billowing from an Aramco oil facility in Abqaiq about 60km (37 miles) southwest of Dhahran in Saudi Arabia's eastern province. - Drone attacks sparked fires at two Saudi Aramco oil facilities early today, the interior ministry said, in the latest assault on the state-owned energy giant as it prepares for a much-anticipated stock listing. Yemen's Iran-aligned Huthi rebels claimed the drone attacks, according to the group's Al-Masirah television. (Photo by - / AFP)        (Photo credit should read -/AFP/Getty Images)
-/AFP/AFP/Getty Images
This AFPTV screen grab from a video made on September 14, 2019, shows smoke billowing from an Aramco oil facility in Abqaiq about 60km (37 miles) southwest of Dhahran in Saudi Arabia's eastern province. - Drone attacks sparked fires at two Saudi Aramco oil facilities early today, the interior ministry said, in the latest assault on the state-owned energy giant as it prepares for a much-anticipated stock listing. Yemen's Iran-aligned Huthi rebels claimed the drone attacks, according to the group's Al-Masirah television. (Photo by - / AFP) (Photo credit should read -/AFP/Getty Images)
Now playing
02:21
Houthi rebels claim drone attacks on Saudi oil facilities
View of the construction site of the Taishan Nuclear Power Plant in Taishan city, south China's Guangdong province, 12 September 2012.
Zhou huadong/Imaginechina/AP
View of the construction site of the Taishan Nuclear Power Plant in Taishan city, south China's Guangdong province, 12 September 2012.
Now playing
03:30
Concerns over possible leak at nuclear plant in southern China
screengrab japan lonely death
CNN
screengrab japan lonely death
Now playing
04:04
Inside Japan's growing 'lonely death' clean-up service
Israel's Prime Minister Benjamin Netanyahu attends a special session to vote on a new government at the Knesset in Jerusalem, on June 13, 2021. - A delicate eight-party alliance united by animosity for Netanyahu is poised to take over with right-wing Naftali Bennett as prime minister, if the coalition deal passes today's slated parliamentary vote. (Photo by Emmanuel DUNAND / AFP) (Photo by EMMANUEL DUNAND/AFP via Getty Images)
Emmanuel Dunand/AFP/Getty Images
Israel's Prime Minister Benjamin Netanyahu attends a special session to vote on a new government at the Knesset in Jerusalem, on June 13, 2021. - A delicate eight-party alliance united by animosity for Netanyahu is poised to take over with right-wing Naftali Bennett as prime minister, if the coalition deal passes today's slated parliamentary vote. (Photo by Emmanuel DUNAND / AFP) (Photo by EMMANUEL DUNAND/AFP via Getty Images)
Now playing
02:39
Former ally replaces Netanyahu as Israeli prime minister
CCTV via AFP
Now playing
01:54
Video of explosion aftermath in China shows a harrowing picture
Employees prepare the National Stadium for the Copa America soccer tournament in Brasilia, Brazil, Friday, June 11, 2021. The stadium will host the opening game on June 13. (AP Photo/Eraldo Peres)
Eraldo Peres/AP
Employees prepare the National Stadium for the Copa America soccer tournament in Brasilia, Brazil, Friday, June 11, 2021. The stadium will host the opening game on June 13. (AP Photo/Eraldo Peres)
Now playing
02:26
Bolsonaro's boast to host Copa América despite Covid-19 pandemic
CNN
Now playing
01:35
Boris Johnson asked if he agrees that Putin is a 'killer'
TOPSHOT - Britain's Queen Elizabeth II (C) attempts to cut a cake with a sword, lent to her by The Lord-Lieutenant of Cornwall, Edward Bolitho, to celebrate of The Big Lunch initiative at The Eden Project, near St Austell in south west England on June 11, 2021. (Photo by Oli SCARFF / POOL / AFP) (Photo by OLI SCARFF/POOL/AFP via Getty Images)
Oli Scarff/AFP/Pool/Getty Images
TOPSHOT - Britain's Queen Elizabeth II (C) attempts to cut a cake with a sword, lent to her by The Lord-Lieutenant of Cornwall, Edward Bolitho, to celebrate of The Big Lunch initiative at The Eden Project, near St Austell in south west England on June 11, 2021. (Photo by Oli SCARFF / POOL / AFP) (Photo by OLI SCARFF/POOL/AFP via Getty Images)
Now playing
00:54
Watch the Queen cut a cake with a sword
Vladimir Putin NBC intv
NBC
Vladimir Putin NBC intv
Now playing
04:22
Hear how Putin compared Donald Trump to Joe Biden
cctv
Now playing
01:02
Never-before-seen Great Wall fort discovered
peskov
CNN
peskov
Now playing
02:34
Kremlin spokesman speaks on state of US-Russia relations
Now playing
04:00
At least 7 Nicaraguan opposition leaders detained ahead of election
US President Joe Biden, Canada's Prime Minister Justin Trudeau, Italy's Prime minister Mario Draghi, President of the European Commission Ursula von der Leyen, President of the European Council Charles Michel, Japan's Prime Minister Yoshihide Suga, Germany's Chancellor Angela Merkel, France's President Emmanuel Macron and British Prime Minister Boris Johnson sit around the table at the start of the G7 summit in Carbis Bay, Cornwall on June 11, 2021.
LEON NEAL/AFP/POOL/Getty Images
US President Joe Biden, Canada's Prime Minister Justin Trudeau, Italy's Prime minister Mario Draghi, President of the European Commission Ursula von der Leyen, President of the European Council Charles Michel, Japan's Prime Minister Yoshihide Suga, Germany's Chancellor Angela Merkel, France's President Emmanuel Macron and British Prime Minister Boris Johnson sit around the table at the start of the G7 summit in Carbis Bay, Cornwall on June 11, 2021.
Now playing
01:27
What is the G7?
screengrab china elephants
CCTV
screengrab china elephants
Now playing
03:06
Elephant migration may reveal serious problem for China
Britain's Prime Minister Boris Johnson (R) speaks with US President Joe Biden while they walk at Carbis Bay, Cornwall on June 10, 2021, ahead of the three-day G7 summit being held from 11-13 June. - G7 leaders from Canada, France, Germany, Italy, Japan, the UK and the United States meet this weekend for the first time in nearly two years, for the three-day talks in Carbis Bay, Cornwall. - (Photo by TOBY MELVILLE / POOL / AFP) (Photo by TOBY MELVILLE/POOL/AFP via Getty Images)
TOBY MELVILLE/AFP/POOL/AFP via Getty Images
Britain's Prime Minister Boris Johnson (R) speaks with US President Joe Biden while they walk at Carbis Bay, Cornwall on June 10, 2021, ahead of the three-day G7 summit being held from 11-13 June. - G7 leaders from Canada, France, Germany, Italy, Japan, the UK and the United States meet this weekend for the first time in nearly two years, for the three-day talks in Carbis Bay, Cornwall. - (Photo by TOBY MELVILLE / POOL / AFP) (Photo by TOBY MELVILLE/POOL/AFP via Getty Images)
Now playing
01:58
See Boris Johnson's reaction to Biden's joke about their wives
Britain's Catherine, Duchess of Cambridge and US First Lady Jill Biden visit Connor Downs Academy in Hayle, Cornwall on the sidelines of the G7 summit on June 11, 2021. (Photo by DANIEL LEAL-OLIVAS / various sources / AFP) (Photo by DANIEL LEAL-OLIVAS/AFP via Getty Images)
Daniel Leal-Olivas/AFP/Getty Images
Britain's Catherine, Duchess of Cambridge and US First Lady Jill Biden visit Connor Downs Academy in Hayle, Cornwall on the sidelines of the G7 summit on June 11, 2021. (Photo by DANIEL LEAL-OLIVAS / various sources / AFP) (Photo by DANIEL LEAL-OLIVAS/AFP via Getty Images)
Now playing
01:26
See Jill Biden and the Duchess of Cambridge host school roundtable
CNN —  

Yemen’s Houthi rebels have attacked Saudi Arabia’s oil facilities with drones, the Houthi-run Al-Masirah news agency said Saturday.

A Yemen armed forces spokesman was quoted by the agency as saying the Houthis successfully carried out a “large-scale” operation with 10 drones targeting Saudi Aramco oil facilities in Abqaiq and Khurais.

But preliminary indications are that the attacks Saturday that disrupted about half of the kingdom’s oil capacity did not originate from Yemen and likely originated from Iraq, according to a source with knowledge of the incident. The same official said the damage was caused by an armed drone attack.

CNN National Security Analyst Peter Bergen said there have been more than 200 drone attacks launched by Houthi rebels from Yemen into Saudi Arabia, and none have been as effective as Saturday’s attack, lending credence to the belief that the attack did not originate from Yemen.

The Saudi interior ministry said the drone attacks caused fires at two facilities of the state-owned oil company. In a statement posted on Twitter, the ministry said the fires were under control and that authorities are still investigating the incident.

The Yemen armed forces spokesman said the operation was a “legitimate and natural” response to “the enemy’s aggression and blockade” of Yemen.

Saudi Arabia has been leading a military campaign to quash the Houthi rebels in Yemen since March 2015. The conflict is widely seen as a proxy war between the Saudis and Iran, which has been backing the Houthis.

“We promise the Saudi regime that the next operation will be wider and more painful if the blockade and aggression continues,” the spokesman added.

The Saudi-led coalition battling the Houthi rebels said in a statement it’s investigating the attacks and would confront “terrorist” threats to global energy security.

One of the facilities, at Abqaiq, is the company’s largest oil-processing facility and the largest crude oil stabilization plant in the world, according to the oil company, Aramco.

Saudi Arabia produces approximately 10% of the total global supply of 100 million barrels per day.

People with knowledge of Saudi’s oil operations told CNN that capacity at Aramco’s oil facilities is “down at this stage by 5 million barrels a day,” meaning 5% of the daily global oil is affected.

Aramco “hopes to have that capacity restored within days,” the source said.

The International Energy Agency is closely “monitoring the situation,” the IEA said in a tweet. For now, “markets are well supplied with ample commercial stocks,” the IEA said.

US President Donald Trump called Saudi Crown Prince Mohammad bin Salman on Saturday to offer his support for the country’s self-defense, White House Deputy Press Secretary Judd Deere said in a statement.

“The United States strongly condemns today’s attack on critical energy infrastructure, Deere said. “Violent actions against civilian areas and infrastructure vital to the global economy only deepen conflict and mistrust.”

The US government “remains committed to ensuring global oil markets are stable and well supplied,” the spokesman said.

01:44 - Source: CNN
Saudi Arabia replaces oil minister with Prince Abdulaziz

James Rogers, a security expert with expertise in drones and a visiting research fellow at the Department of International Security Studies at Yale University, said the United Nations has been investigating the drones, which have a range of 1,450 kilometers (900 miles). He said the range means that Houthi forces can target sites in Saudi Arabia from their stronghold in Yemen.

“It is quite an impressive, yet worrying, technological feat,” he said. “Long-range precision strikes are not easy to achieve and to cause the substantial fires in Abqaiq and Khurais highlights that this drone has a large explosive yield.”

The United Nations special envoy to Yemen, Martin Griffiths, said he’s quite concerned over the attacks.

“The recent military escalation is extremely worrying,” Griffiths said in a statement, adding that such attacks “pose a serious threat to regional security.”

The UK Foreign Office called the attacks “completely unacceptable.”

“Threatening civilian areas and commercial infrastructure is dangerous, provocative and completely unacceptable,” the office said in a statement. “This escalation also undermines UN-led efforts to end the conflict in Yemen.”

CNN’s John Defterios contributed to this report.