US Defense Secretary Jim Mattis told reporters Tuesday that the uproar surrounding the Trump administration's handling of confidential information "never even came up" in his most recent round of talks with US allies.

On Monday, media reported that President Donald Trump had last week disclosed highly classified information on the so-called "Islamic State" (IS) terrorist group to the Russian foreign minister, Sergey Lavrov.

Critics alleged that the decision to share the information jeopardized a crucial intelligence source. The White House fiercely denied the allegations, saying that Trump's talks with Russian emissaries were "wholly appropriate."

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While affirming that he was not worried about Trump's disclosure to Russian officials, Mattis admitted that he had no details about Trump's conversation with Lavrov and knew little more about the furor other than what he had "read in the newspapers."

Earlier on Tuesday, US National Security Adviser H.R. McMaster said that Trump had "in no way compromised" his sources by sharing the sensitive intelligence, adding that "the president wasn't even aware of where this information came from."

Trump went on to tweet that, as president, he had the "absolute right" to declassify and share any such information related to terrorism with Russia.

The Trump administration has come under intense scrutiny over accusations that the president's aides had colluded with Russian officials during last year's presential campaign.

In February, Trump fired his former National Security Advisor Michael Flynn after it was revealed that he had lied about the nature and extent of his ties to Russian diplomats.

Then, last week, Trump fired FBI Director James Comey, who had led the bureau's probe into the president's links with Russia. On Tuesday it was reported that Trump may have urged Comey to drop the FBI's probe into Flynn's ties with Russia, in what some critics have called a possible act of obstruction of justice.

dm/gsw (Reuters, AP)