US President Donald Trump under no investigation, says personnel attorney

US President Donald Trump is not facing any probe for obstruction of justice, a member of his legal team said on Sunday, contradicting his own assertion that he was under investigation for firing former FBI Director James Comey and being the target of a "witch hunt".

"Let me be clear here, the president is not and has not been under investigation for obstruction. There is not an investigation of the president of the United States, period," said Jay Sekulow, chief counsel of the American Center for Law and Justice.

Earlier on Friday, Trump said he was being investigated for firing former FBI Director James Comey.

"I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director! Witch Hunt," Trump said in a tweet.

Sekulow, however, said Trump's tweet was in response to a "fake" media report with no "documented sources".

"The tweet from the president was in response to the five anonymous sources purportedly leaking info to the Washington Post. He's not afraid of the investigation - there is no investigation," Sekulow told NBC channel.

"Let me clear. The president's not under investigation, as James Comey said in his testimony, that the president was not the target of investigation on three different occasions," Sekulow told CNN in another interview.

"The President is not a subject or target of an investigation. That tweet was in response to a "Washington Post" story that ran with five unnamed sources, without identifying the agencies they represented, saying that the special counsel had broadened out his investigation to include the president," he said.

According to the Washington Post report, Trump was being investigated for possible obstruction of justice by the special counsel appointed to probe alleged Russian meddling in the 2016 presidential polls.

"The president was responding to that particular statement from The Washington Post, again with five anonymous sources. And again without even identifying the agencies. So no, the president's not under investigation, has not been," he said.

"So here's what you have: the president issued that tweet, that social media statement, based on a fake report, a report with no documented sources, from The Washington Post, he said.

Sekulow said it was ironic that a leak would take place by five anonymous sources saying that the special counsel had increased the scope of their investigation without even identify the agencies upon which those individuals were speaking.

"So the president responds - I want to be crystal clear here. The president's response was as it related to The Washington Post report. He cannot in a Twitter statement include all of that in there, but The Washington Post statement came out that morning," he said.

"So there can be no confusion. No confusion. The president is not under investigation," Sekulow said.