Donald Trump has expressed surprise at the FBI's raid and search of his former campaign manager Paul Manafort's home as part of the Russia investigation – saying it sends “a very strong signal”.

The raid was carried out by investigators working as part of Special Counsel Robert Mueller's probe into Russian meddling in the 2016 US election and any potential ties to the Trump campaign.

“I thought [the raid] was a very, very strong signal, or whatever,” Mr Trump told reporters during a working vacation at his golf club in New Jersey. “I know Mr Manafort. Haven’t spoken to him for a long time, but I know him…. I thought it was a very – you know, they do that very seldom, so I was surprised to see it. I was very, very surprised to see it.”

Mr Trump also said he had no thoughts about firing Mr Mueller, whose investigation he has frequently denounced as a “witch hunt” or “hoax”.

“I haven’t given it any thought," Mr Trump told reporters. “I’ve been reading about it from you people. You say, ‘Oh, I’m going to dismiss him.’ No, I’m not dismissing anybody.”

Deputy Attorney General Rod Rosenstein appointed Mr Mueller to lead the Russia investigation in May after Mr Trump fired FBI Director James Comey, who had had originally been in charge of the bureau’s probe. Mr Comey testified to a Senate committee that he believes he was fired because of the way he had been handling the Russia inquiry.

The US Attorney General is normally in charge of appointing a special counsel. However, Attorney General Jeff Sessions could not appoint one because he had recused himself from the Russia investigation in March after it was revealed he had undisclosed contacts with a Russian official during the presidential campaign.

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Washington had been on high alert for the past few weeks over whether Mr Trump would fire Mr Sessions. Along with attacking the attorney general on Twitter, the President has said he would never have appointed Mr Sessions had he known the former Alabama senator would recuse himself.

When asked about his relationship with Mr Sessions on Thursday, Mr Trump said, “It is what it is. It’s fine.”

“He’s working hard on the border. I’m very proud of what we’ve done at the border,” Mr Trump said, likely referring to Mr Sessions’ crackdown on illegal immigration.

Mr Trump said he supports the ongoing Russia probes, including those being carried out on Capitol Hill, where multiple panels are also investigating possible collusion between Trump associates and the Russian government.

“I want them to get on with the task,” Mr Trump said. “But I also want the Senate and the House to come out with their findings.”