US President Donald Trump has acknowledged that he shared intelligence information with top Russian envoys at an Oval Office meeting last week.
"As President I wanted to share with Russia (at an openly scheduled W.H. meeting) which I have the absolute right to do, facts pertaining ... to terrorism and airline flight safety," he wrote on Twitter on Tuesday.
"Plus I want Russia to greatly step up their fight against ISIS & terrorism," he continued.
Trump's early morning tweet appeared to fly in the face of repeated White House denials of a Washington Post report on Monday.
The newspaper reported that Trump revealed highly classified information about the Islamic State terrorist group during his talks with Russian Foreign Minister Sergey Lavrov and Russian ambassador to the US Sergey Kislyak on May 10, citing current and former administration officials.
Late on Monday, the White House released several statements that blasted the story as "false." The Russian Foreign Ministry called the story "fake."
Maria Zakharova, a spokesperson for Foreign Ministry, left a dismissive post about the report on her Facebook page: "Guys, have you been reading the American newspapers again?" she wrote. "You shouldn't read them. You can put them to various uses, but you shouldn't read them. Lately it's become not only harmful, but dangerous, too."
Secretary of state, Rex Tillerson, and national security adviser, H.R. McMaster, issued statements on Monday saying no sources, methods or military operations were discussed at the Russian meeting.
McMaster said the story, initially reported by the Washington Post, was false.
The US officials told Reuters that while the president has the authority to disclose even the most highly classified information at will, in this case he did so without consulting the ally that provided it, which threatens to jeopardise a long-standing intelligence-sharing agreement.
Bob Corker, the Republican head of the Senate Foreign Relations Committee, called the allegations "very, very troubling."
"Obviously, they're in a downward spiral right now," he said on Monday, "and they've got to come to grips with all that's happening."
The latest controversy comes as the White House continues to reel from the fallout over Trump's abrupt firing of FBI Director James Comey last week and amid congressional calls for an independent investigation into allegations of Russian meddling in the 2016 US election.
