Mr Trump also told NBC News it was his decision alone to sack James Comey.

Mr Comey was leading an inquiry into alleged Russian meddling in the US election and possible collusion between Trump campaign officials and Moscow.

Mr Trump has dismissed the probe as a "charade", a claim directly contradicted by Mr Comey's successor.

In his first interview since firing the FBI director, Mr Trump told NBC News on Thursday he had asked Mr Comey whether he was under investigation. "I said, if it's possible would you let me know, 'Am I under investigation?' He said: 'You are not under investigation.'"

BBC News