CNN has confirmed that Lt. Gen. Michael Flynn has resigned from his position as national security adviser. On Monday evening, two White House sources revealed to CNN that Flynn handed in his letter of Resignation to President Trump and Vice President Pence, who have accepted his resignation without question.

Flynn was vulnerable to Russian blackmail, claims White House

Flynn's departure is the result of media reports which surfaced earlier in the day, in which the Justice Department warned the Trump administration in January that Flynn intentionally misled White House officials about his communications with Russia's ambassador to the U.S., thereby making the National Security Adviser vulnerable to Russian blackmail.

In a copy of Flynn's resignation letter obtained by CNN, he acknowledges briefing then Vice President-elect Mike Pence with incomplete information regarding his communications with the Russian ambassador. In his resignation letter Flynn apologizes to President Trump and Vice President Pence.

Flynn's departure after less than one month on the job makes him one of the shortest-tenured presidential advisers in recent history. According to CNN, Flynn will be replaced by Gen. Keith Kellogg, formerly the chief of staff for the National Security Council.

Flynn's troubles began last week after a Washington Post story publicized his conversations with ambassador Sergey Kislyak regarding the sanctions levied by Barack Obama over Russia's alleged interference in the 2016 presidential election, which violates a law prohibiting private citizens from directly negotiating with foreign governments.

Possibly replacements include Gen. Petraeus and Vice Admiral Harward

Gen. Kellogg will serve as interim National Security Adviser, but is expected to contend for the full-time position. Other contenders for the adviser position include Gen. David Petraeus and former Vice Admiral Bob Harward.

Flynn was one of Donald Trump's earliest advisers on national security issues, and was a fixture on the campaign trail during Trump's 2016 presidential campaign.