London (CNN) UK Prime Minister Theresa May declined to say Wednesday whether she still had full confidence in US President Donald Trump in the wake of reports that he shared top secret intelligence with Russia , instead stressing that Britain and the United States have "a very special relationship" and would continue to work together.

Revelations that Trump reportedly disclosed highly sensitive information to top Russian officials in a meeting last week have raised questions among some allied intelligence agencies about the security of details they share with their US counterparts.

Israeli intelligence was a source for some of the information about ISIS bomb-making capabilities that the President discussed with Russian diplomats, US and diplomatic officials told CNN on Tuesday.

The White House would not comment on claims Israel was the source. But earlier Tuesday, it insisted that Trump did not risk national security by sharing classified information with top Russian officials, and revealed that the President did not even know the source of the intelligence he divulged.

Asked at an election campaign press conference Wednesday if Trump had her "full confidence," May said: "We have a very special relationship, as you know, with the United States of America. This is the most important defense and security relationship that we have around the world."

May, who was the first foreign leader to visit Trump after his inauguration and whose ruling party is expecting to win the UK general election next month, went on to praise Trump's "100% commitment" to NATO, saying it was "an important bedrock of our security and the bedrock of the security in Europe."

Asked if she felt more reluctant to share secrets with the US now, May said decisions about what Trump discussed with people were "a matter for President Trump" and that Britain would continue to work with and share intelligence with the US.

US President Donald Trump meets with Russian Foreign Minister Sergey Lavrov, second left, at the White House on May 10.

Trump's national security adviser, H.R. McMaster, said Tuesday that Trump's behavior at the Oval Office meeting last week was "wholly appropriate."

Intelligence-sharing relationships

The US is part of the so-called "Five Eyes" agreement -- along with Britain, Canada, Australia and New Zealand -- which calls for open sharing among member nations of a broad range of intelligence.

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.

May is not the only leader to rally behind the longstanding Five Eyes agreement.

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."

Netanyahu, Trump speak

Israel's government has remained close-lipped on the matter.

Israeli Prime Minister Benjamin Netanyahu and Trump spoke on the phone Tuesday night for about 20 minutes, according to the Israeli Prime Minister's Office. "The only topic discussed was the upcoming visit," the office said in a statement to CNN.

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Israel's ambassador to the US, Ron Dermer, would not comment on the intelligence, but expressed confidence in the relationship between the two countries.

Speaking to CNN before reports emerged that Israel may be the source of the intel, former Israeli spymaster Danny Yatom said the revelation of classified intelligence by Trump "is a very disturbing issue and might cause a lot of danger."

Yatom, who led the Mossad, Israel's spy agency, from 1996-1998, said: "The source might be under very serious danger and a consequence may be that the friendly country will stop conveying such sensitive information to the United States."

He added: "The enemy can very easily identify and recognize where the information came from and start searching for collaborators."

Israel also shares strong security coordination with the Russians, particularly over airspace in Syria, but Russia's close ties to Iran mean Israel must be careful with its information. Yatom said it appeared this information wasn't intended for the Russians.

'Basis of trust'

Former defense secretary and CIA Director Leon Panetta told CNN's Chris Cuomo on Tuesday that the fallout of breaching the trust of key allies by disclosing information could be significant.

"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."