United States President Joe Biden has pardoned his son Hunter ahead of his sentencing on gun and tax convictions despite a previous pledge not to use his presidential powers to grant him a reprieve.

Biden said on Sunday that his son had been “singled out” and “selectively, and unfairly” prosecuted due to his family name.

“There has been an effort to break Hunter – who has been five and a half years sober, even in the face of unrelenting attacks and selective prosecution,” Biden said in a statement released by the White House.

“In trying to break Hunter, they’ve tried to break me – and there’s no reason to believe it will stop here. Enough is enough.”

Biden’s decision comes weeks before Hunter Biden was set to face sentencing for a string of felonies related to making a false statement about his drug use during a gun background check and failing to pay at least $1.4m in taxes.

In justifying his decision, Biden said that people are “almost never” brought to trial for wrongly filling out a gun purchase form and that those who pay their taxes late usually receive “non-criminal resolutions”.

“For my entire career I have followed a simple principle: just tell the American people the truth. They’ll be fair-minded. Here’s the truth: I believe in the justice system, but as I have wrestled with this, I also believe raw politics has infected this process and it led to a miscarriage of justice – and once I made this decision this weekend, there was no sense in delaying it further,” Biden said.

“I hope Americans will understand why a father and a President would come to this decision.”

In June, Biden had flatly ruled out the possibility of granting his son a pardon or commuting his sentence.

“I said I will abide by the jury decision. I will do that and I will not pardon him,” Biden had said.

The White House had reiterated Biden’s intention not to pardon his son as recently as November 8, when press secretary Karine Jean-Pierre told reporters: “Our answer stands, which is no.”