The report claims that Trump relayed sensitive details gathered through an intelligence-sharing arrangement with an allied nation.
This could potentially damage several key relationships between the US and its partners that depend on the trust that shared information will not be disclosed -- particularly with countries that are viewed as adversaries.
"The partner had not given the United States permission to share the material with Russia, and officials said Trump's decision to do so endangers cooperation from an ally that has access to the inner workings of the Islamic State," according to the Post's report.
Trump "revealed more information to the Russian ambassador than we have shared with our own allies," the report said.
The many paths from Trump to Russia
Early responses to the bombshell report indicate that, if true, handling sensitive details in this manner would have broad implications on US partnerships around the world and could place the lives of agents in the field at risk.
"Never before have I witnessed a senior government official so carelessly threaten an intelligence-sharing relationship," a former senior intelligence official told CNN.
The US is part of the so-called "Five Eyes" agreement (along with Great Britain, Canada, Australia and New Zealand), which calls for open sharing among member nations of a broad range of intelligence.
In an interview with Adelaide Radio on Tuesday, Australian Prime Minister Malcolm Turnbull declined to address the claims against Trump directly but did reaffirm his confidence in the relationship between his nation and the US.
"I have great confidence in our alliance," Turnbull said. "It is the bedrock of our national security. It was reinforced, yet again, when President Trump and I met on the Intrepid in New York just a few days ago."
But former defense secretary and CIA Director Leon Panetta warned Tuesday that the fallout of breaching the trust of key allies by disclosing information could be significant.
"He cannot just go ahead and reveal classified info without creating some huge problems in the intelligence community," Panetta said on CNN's "New Day."
"You don't just get intelligence out of thin air. You get intelligence because we deploy spies, because we deploy people who are willing to put their lives on the line and because we work with other intelligence agencies around the world that help provide that kind of information," he said. "But it is done on the basis of competence and trust."
According to Panetta, the ally who provided the information that was reportedly relayed to the Russians could cut off any type of intelligence provided to the US in the future.
The US also maintains open intelligence sharing relationships with allies like France, Germany and Japan. In the Middle East, the US formally and informally shares information with several countries in the fight against ISIS and other terror groups including Jordan, Egypt, Saudi Arabia, the United Arab Emirates and Turkey, among others.
Trump plans to speak with King Abdullah of Jordan by phone and meet with President Erdogan of Turkey on Tuesday. Both Jordanian and US officials said Tuesday the call with Abdullah was scheduled last week and is unrelated to the Russia meeting.
Two former officials knowledgeable about the situation tell CNN that the main points of the Post story are accurate
that the President shared classified information with the Russian foreign minister.
The information did not directly reveal the source of the intelligence but intelligence officials tell CNN that there is concern that Russia will be able to figure out the highly sensitive source.
There is some disagreement, according to one of the sources, as to how far the President went.
The intelligence relates to what is known as a sensitive access program, or SAP, which covers some of the most classified information and is protected with unique access and security protocols.
And the potential consequences could hardly be more serious, former CIA case officer Bob Baer told CNN's Erin Burnett.
"The President, by revealing this to the Russians, has lost control of this information. It's going to go to the Syrians, It's going to go to the Iranians -- Russian allies," Baer said.
"The ability to protect that source whoever he is, wherever he is has been seriously undermined ... If a CIA officer had revealed this information to the Russians, he would be fired instantly."
Beyond jeopardizing the trust of key allies, lawmakers and intelligence officials warn that disclosing this type of information could impact US efforts to counter an ISIS plot to place explosives in laptops and other electronic devices to evade airport security screening methods.
While the White House said that Trump did not relay information about "intelligence sources or methods," nor did the President "disclose any military operations that weren't already publicly known," the administration did not address the Post's reporting that Trump described details about how ISIS hopes to use laptop computers as bombs on planes.
"This is infuriating if true," a former US intelligence officer told CNN about the Washington Post's report. "If the information itself was specific enough, it implicitly discloses sources and methods."
CNN has previously reported
that the US government was concerned that even revealing some specific details about efforts to counter the ISIS plot would endanger sources and methods, even if sources and methods were not specifically described.
According to the Post, "Trump revealed the city in the Islamic State's territory where the US intelligence partner detected the threat" -- a detail CNN agreed to withhold in its report last month at the request of US government officials.
Those officials told CNN at the time that if the name of the city was disclosed then it would reveal crucial information about how the United States learned about the threat.
That intelligence led the Trump administration to ban travelers flying out of 10 airports in eight countries in the Middle East and Africa from carrying electronic devices larger than cell phones aboard planes. The United Kingdom, which possessed the same intelligence, placed a similar prohibition on passengers flying from six countries, including two that were not on the US list.
Officials told CNN that the ban came about following the collection of intercepted material and "human intelligence."
The Department of Homeland Security is reportedly considering expanding the electronics ban to flights from Europe to the United States.
Many lawmakers expressed concern Monday over what the report could mean for the US's relationships with its allies.
"This bombshell report is astonishing and appalling - betraying our allies, endangering safety of sources, and sabotaging our war against ISIS," said Democratic Sen. Richard Blumenthal in a tweet.
"Trump owes us an explanation for putting lives at risk- he's betrayed his first responsibility to the safety and security of the United States," he added.