Trump's lawyer says President not informed he is under investigation

One of President Donald Trump's personal lawyers said in television interviews on Sunday that the president was not under investigation for obstruction of justice, but when pressed on the assertion, said he was not certain.

"The fact of the matter is the president has not been and is not under investigation," Jay Sekulow, a new member of Trump's legal team, said on CBS' "Face the Nation" in one of four interviews he gave on Sunday.

Sekulow, contended tweet by the President this week saying "I am being investigated", was not a confirmation of the investigation, but instead a response to a report in The Washington Post.

"That tweet was in response to a Washington Post story that ran with five unnamed sources," Sekulow said in an interview that aired Sunday on CNN's "State of the Union."

Trump tweeted on Friday: "I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director! Witch Hunt".

The Washington Post story cited five officials who had been briefed on interview requests from special counsel Robert Mueller with three top intelligence officials to see if Trump had attempted to obstruct justice.

Challenged on "Fox News Sunday" about the issue, Sekulow said he could not be certain Trump was not under investigation but that no one had notified the legal team if that was the case.

It is common for subjects of federal investigations not to know they are under scrutiny, especially in the initial phases.

A source familiar with the Mueller probe said on Thursday that investigators would have to gather a large amount of evidence before an interview with the president would be warranted.

Trump, who has denied any collusion between his campaign and Russia, has frequently lashed out about the allegations, which have overshadowed his administration's efforts to overhaul the healthcare system, cut taxes and boost jobs.

Mueller, the special counsel named by the Justice Department to probe the Russia matter, is investigating whether anyone associated with Trump or his campaign had any illegal dealings with Russian officials or others with ties to the Kremlin.

Russian officials have denied meddling in the US election.