US President Donald Trump has allegedly disclosed highly classified information to Russia's foreign minister about a planned Islamic State operation, two U.S. officials said on Monday, plunging the White House into another controversy just months into Trump's short tenure in office.

 The intelligence, shared at a meeting last week with Russian Foreign Minister Sergei Lavrov and Russian Ambassador Sergei Kislyak, was supplied by a U.S. ally in the fight against the militant group, both officials with knowledge of the situation said.

The White House declared the allegations, first reported by the Washington Post, incorrect.

"The story that came out tonight as reported is false," H.R. McMaster, Trump's national security adviser, told reporters at the White House, adding that the leaders reviewed a range of common threats including to civil aviation.

"At no time were intelligence sources or methods discussed. The president did not disclose any military operations that were not already publicly known...I was in the room. It didn't happen," he said.

Russia's foreign ministry said reports that Trump had revealed highly classified information were "fake".

The White House also released a statement from Secretary of State Rex Tillerson, who said the Oval Office meeting focused on counterterrorism, and from Deputy National Security Adviser Dina Powell, who called the Washington Post story false.

Still, the news triggered concern in Congress.

The Senate's No. 2 Democrat, Dick Durbin, called Trump's conduct "dangerous" and "reckless"
Bob Corker, the Republican head of the Senate Foreign Relations Committee, called the allegations "very, very troubling" if true.

“Obviously, they’re in a downward spiral right now and they’ve got to come to grips with all that’s happening," he said of the White House.