Washington, Dec 11 (IANS): US President Donald Trump has expressed concern that he could be impeached when Democrats take over the House and saw it as a "real possibility", a source close to him told CNN.

But Trump isn't certain it would happen, the source said on Monday night.

A separate source close to the White House told CNN that aides inside the West Wing believe "the only issue that may stick" in the impeachment process is the campaign finance violations tied to the President's former personal lawyer Michael Cohen's payouts to Stormy Daniels and Karen McDougal, both women have alleged to have affairs with Trump.

Impeachment talk has ratcheted up in recent days following a blockbuster filing from prosecutors in the Southern District of New York.

In the filing, prosecutors directly alleged for the first time that Cohen was being directed by Trump when he broke the law during the 2016 presidential campaign.

Democrats were suggesting that Trump committed an impeachable offence and could be sent to prison when his term in the White House is over.

The incoming chairman of the House Judiciary Committee, Representative Jerry Nadler, said on Sunday the allegations, if proven, would constitute "impeachable offences".

Democratic Senato Chris Coons said earlier on Monday that Trump could be indicted after he leaves office.

White House officials, at the moment, still do not believe that Special Counsel Robert Mueller's investigation into possible collusion will result in impeachment.