US President Donald Trump has launched a fresh Twitter attack on the credibility of his own FBI.

He was responding to disclosures that an FBI agent was removed from special counsel Robert Mueller’s team investigating Russian election meddling because of anti-Trump text messages.

Mr Trump, two days after his former national security adviser Michael Flynn pled guilty to lying to the FBI, again denied that he directed FBI director James Comey to stop investigating Mr Flynn.

The President offered a running Twitter commentary yesterday amid renewed focus on Mr Mueller’s probe and Mr Flynn’s decision to co-operate with the investigation as part of his plea agreement. Democrats said the developments suggested growing evidence of co-ordination between Mr Trump’s circle and Russian meddling in the 2016 presidential election.

California senator Dianne Feinstein, the top Democrat on the Senate Judiciary Committee, said the panel was beginning to see “the putting together of a case of obstruction of justice” against Mr Trump.

She said: “I think we see this in indictments... and some of the comments that are being made. I see this in the hyperfrenetic attitude of the White House, the comments every day, the continual tweets.

“And I see it most importantly in what happened with the firing of director Comey, and it is my belief that that is directly because he did not agree to lift the cloud of the Russia investigation. That’s obstruction of justice.”

In a series of tweets, Mr Trump questioned the direction of the federal law enforcement agency and wrote that after Mr Comey, who Trump fired in May, the FBI’s reputation is “in Tatters – worst in History!”

He vowed to “bring it back to greatness”.The President also retweeted a post saying new FBI director Chris Wray “needs to clean house”. The President seized on reports a veteran FBI counter-intelligence agent was removed from Mr Mueller’s team last summer after the discovery of an exchange of text messages viewed as potentially anti-Trump.

The agent, Peter Strzok, had also worked on the investigation of Democrat Hillary Clinton’s use of a private email server.

Peter Carr, a spokesman for Mr Mueller, said Mr Mueller removed Peter Strzok from the team “immediately upon learning of the allegations”.