US President Donald Trump has filed an appeal to overturn his May 2024 criminal conviction in the hush-money payment case, arguing he is shielded by presidential immunity.

Trump was convicted of 34 felony counts of falsifying business records by a unanimous jury in New York.

In December, citing Trump's imminent return to the White House, a New York judge sentenced Trump to an unconditional discharge, meaning he would not serve time or pay a fine.

"This case should never have seen the inside of a courtroom, let alone resulted in a conviction," Trump's lawyers said in the latest filing.

They described the case as "the most politically charged prosecution in our nation's history".

The Manhattan District Attorney's office, which prosecuted Trump, did not immediately respond to a request for comment.

Prosecutors alleged that in the days before the 2016 election, Trump instructed his personal lawyer, Michael Cohen, to pay $130,000 in hush money to the adult film star Stormy Daniels so she would stay silent about allegations of a sexual encounter with Trump.

The hush-money payment was not illegal, but prosecutors said that when Trump reimbursed Cohen, the payments were fraudulently recorded as legal expenses in order to disguise their true nature.

The spring 2024 trial played out in tandem with Trump's re-election campaign.

During the trial, prosecutors alleged that disguising the payments amounted to a form of election interference as they kept Daniels' allegations from voters. Trump denied the charges and any wrongdoing.

A jury found Trump guilty of all 34 counts of falsifying business records that May, making him the first former or sitting US president to be convicted of a felony.

About a month after his conviction, the US Supreme Court ruled that US presidents had broad immunity from criminal prosecution for "official acts" undertaken during their presidency.

Trump's lawyers in the Manhattan case then argued that the Supreme Court's immunity finding should apply to Trump's hush-money case, and that certain evidence from the trial should have been excluded because it stemmed from Trump's first presidency.

Justice Juan Merchan, who oversaw Trump's hush-money case, rejected the argument. But Trump's team was long expected to appeal.

In their filings, Trump's lawyer wrote that Manhattan District Attorney Alvin Bragg "brought those charges in the middle of a contentious presidential election in which President Trump was the leading Republican candidate.

"These charges against President Trump were as unprecedented as their political context," the lawyers wrote.

They argued that Trump's actions had not violated New York law and are seeking to have the case dismissed.

The case will go before the New York Appellate Division, First Department.

In August, the same court threw out a $500 million civil fraud penalty against Trump that resulted from a separate civil case brought by New York Attorney General Letitia James.

A panel of appellate judges upheld a lower court finding that Trump was liable for fraud, but found the enormous financial penalties the judge had issued were not justified.