Matthew Whitaker’s future at the US Justice Department already appears uncertain after President Donald Trump denied even knowing the man he had named acting attorney general just two days earlier.

The Senate’s top Republican predicted a permanent replacement could be named soon for Mr Whitaker, who is now overseeing the Trump-Russia probe.

The comments from President Trump and Senate Majority Leader Mitch McConnell came as Mr Whitaker’s past business ties and remarks on special counsel Robert Mueller’s Russia investigation and other topics were drawing scrutiny from Democrats and ethics groups.

Speaking to reporters, President Trump said, “I don’t know Matt Whitaker.”

That contradicted President Trump’s remarks on Fox News last month, when he called Mr Whitaker “a great guy” and said, “I mean, I know Matt Whitaker.”

Late on Friday, President Trump said in a tweet Mr that Whitaker was “a highly respected former US Attorney from Iowa” chosen by former attorney general Jeff Sessions to be his chief of staff.

But President Trump emphasised again that he did not know Mr Whitaker.

He also said Mr Whitaker was well regarded by various Iowa Republican leaders and added: “I feel certain he will make an outstanding Acting Attorney General.”

Mr McConnell, meanwhile, said, “I think this will be a very interim AG.”

Another Republican senator, Susan Collins of Maine, said she was concerned by some of Mr Whitaker’s past comments and called for legislation that would place limits on his ability to fire special counsel Mr Mueller.

Russia Probe Protests
Protesters gather in front of the White House in Washington (Andrew Harnik/AP)

That would include specifying that only a Senate-confirmed Justice Department official — which Mr Whitaker is not — could dismiss Mr Mueller.

Mr Whitaker, a Republican Party loyalist and chief of staff for Mr Sessions, was elevated on Wednesday after his boss was forced from his job by President Trump.

The new position handed him oversight of Mr Mueller’s investigation into possible ties between Russia and Mr Trump’s 2016 presidential campaign.

Since Wednesday, Mr Whitaker has faced pressure from Democrats to recuse himself from overseeing Mr Mueller based on critical comments he made about the investigation before joining the Justice Department last year.

Those included an op-ed article in which he said Mr Mueller would be straying outside his mandate if he investigated Trump family finances and a radio interview in which he maintained there was no evidence of collusion between the Kremlin and the Trump campaign.

He also tweeted an ex-prosecutor’s opinion piece that described a “Mueller lynch mob,” which he said was “worth a read”.

There have also been reports about past comments questioning the power and reach of the federal judiciary, and about his ties to an invention-promotion company that was accused of misleading investors.