A judge has demanded more information about US president Donald Trump’s decision to commute the prison sentence of ally and friend Roger Stone.

US District Judge Amy Berman Jackson ordered the parties provide her with a copy of the executive order that commuted Stone’s sentence and clarity on the scope of the order.

Stone was convicted as part of special counsel Robert Mueller’s Russia investigation of making false statements, tampering with a witness and obstructing lawmakers who were examining Russian interference in the 2016 election.

Mr Trump commuted the 40-month sentence handed to Stone on Friday evening, just days before he was to report to prison.

Hours after the judge’s directive, the Justice Department submitted to the court a two-page order making clear that the clemency extended to both Stone’s prison sentence and his supervised release.

In the order, also posted on the website of the Justice Department’s pardon attorney office, Mr Trump wrote that justice would not be served were Stone “to remain confined to his home or serve the said sentence, and the safety of the community will not be compromised if he is released from home confinement and clemency is granted”.

The president told reporters on Monday that he was getting “rave reviews” for his action on Stone and restated his position that the Russia investigation “should have never taken place”.

Democrats were highly critical of Mr Trump’s action on behalf of Stone as having undermined the rule of law, and Senator Mitt Romney, the only Republican to vote to convict the president during his impeachment trial, called the clemency decision “unprecedented, historic corruption”.

President Donald Trump was criticised for the decision
President Donald Trump was criticised for the decision (Evan Vucci/AP)

Mr Mueller himself defended the Stone prosecution in a Washington Post opinion piece in which he said Stone “remains a convicted felon, and rightly so”.

In an interview with Fox News on Monday, Stone, 67, described the criminal investigation and prosecution as the “most horrible experience you can have”.

Stone said that he knew Mr Trump might “take some shots” for the commutation, but added: “I think most people, most fair-minded people, understand he saved my life and, at least on paper, he gave me a chance to fight for vindication.”