He echoed the argument his lawyers made in a January memo to the US special counsel leading the investigation.

In his tweet, Mr Trump once again lashed out at the inquiry into whether his election campaign had colluded with Russia or obstructed justice.

Constitutional scholars are divided on whether a president can pardon himself.

• Could the US president pardon himself?
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Also on Monday morning, White House adviser Kellyanne Conway was asked by a reporter why the president talked about pardoning himself.

She replied: "Why would he need to pardon himself if he's done nothing wrong? You just like to engage in these hypothetical exercises constantly.

"I presume it's easier than understanding the ins and outs of North Korea and trade policy."

Mr Trump's tweet comes a day after one of his lawyers addressed the self-pardon issue on Sunday talk shows.

Rudy Giuliani appeared on ABC's This Week programme and was asked whether Mr Trump had the power to pardon himself.

Mr Giuliani, the head of Mr Trump's legal team, said he "probably does", but added: "He has no intention of pardoning himself."

He went on: "I think the political ramifications of that would be tough. Pardoning other people is one thing. Pardoning yourself is another."

Speaking on CNN on Sunday, House Republican Majority Leader Kevin McCarthy said that no president should pardon himself.