A deal that would have Hunter Biden plead guilty to a pair of misdemeanour tax charges while avoiding prosecution on a gun charge hit a last-minute snag, with the judge in the case unexpectedly putting off her decision.

The federal judge overseeing the case, Maryellen Noreika, deferred her decision on approving the deal between Biden and federal prosecutors on Wednesday afternoon.

During the hearing in the Federal District Court in Wilmington, Delaware, Judge Noreika asked the two sides to make changes to the deal that would clarify her role and insert language that limits the scope of broad immunity from prosecution it would grant to Biden on his business dealings.

The decision delays, at least briefly, a proposed deal that came after a years-long investigation by the federal prosecutor in Delaware, David C. Weiss, a Trump appointee. Under the terms of the proposed agreement, Hunter Biden would not serve time in prison.

The hearing was going smoothly before Judge Noreika questioned whether the agreement meant that Biden would be immune from prosecution for other possible crimes in perpetuity. When a top prosecutor in the case said it would not, Chris Clark, Biden’s lead lawyer, said the government’s position would make the pact “null and void”.