Michael Flynn's days in the White House may be numbered

New details on National Security Adviser Michael Flynn's correspondence with Russia have emerged, after US officials say the White House was warned late last month that Flynn had misled officials and that he was susceptible to Russian blackmail.

According to The Washington Post, former acting Attorney General Sally Yates, who was fired by President Donald Trump, told the White House that she believed Flynn had misled officials about the extent of his communication with Russia's ambassador to the US, Sergey Kislyak.

Yates' message came at a time when concerns arose after Flynn told Vice ­President Mike Pence that he denied discussing US sanctions against Russia with Kislyak.

Former Director of National Intelligence, James Clapper and former CIA Director John Brennan both said at the time that "Flynn had put himself in a compromising position," with Russia and agreed that Pence deserved to know he had been misled, according to officials cited by The Post. It remains unclear what White House counsel Donald McGahn did with that information.

Flynn reportedly apologized on Monday to Pence, saying that he may have discussed the Obama administration's sanctions with Kislyak before Trump was sworn in. Prior to this, Flynn denied allegations of talks with Kislyak, including one on the day President Barack Obama announced new sanctions on Russia for that country's attempts to disrupt the US election.

As the evidence of discussions grew, including transcripts of calls, Flynn's spokesman said that Flynn "indicated that while he had no recollection of discussing sanctions, he couldn't be certain that the topic never came up."

If the allegations are true, Flynn's actions would be in contention with the Logan Act, which prohibits US citizens from interfering in foreign diplomacy. However, a case involving the 1799 statute has never been successfully prosecuted.

Earlier Monday, press secretary Sean Spicer said in a statement that the White House was "evaluating the situation" with Flynn. A senior Trump administration official also said that they were aware of the situation and that they were "working on this for weeks."