Donald Trump with Russian Foreign Minister Sergei Lavrov (left) and Russian Ambassador to the US Sergei Kislyak. Pic/AFP

Washington: President Donald Trump disclosed highly classified information to Russia's foreign minister about a planned IS operation, two US officials said on Monday.

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

The White House declared the allegations, reported by the Washington Post, incorrect. "The story that came out tonight as reported is false," HR McMaster, Trump's national security adviser, told reporters.

"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. Agencies