Joe Biden has so far been muted on Donald Trump's trial as he campaigns to retain the presidency
Joe Biden has so far been muted on Donald Trump's trial, but we are seeing a changing strategy AFP

President Joe Biden has called former President Donald Trump a "convicted felon" who "snapped" following his loss in 2020 election.

Speaking at a campaign event in Greenwich, Connecticut, on Monday, Biden also took swipes at the narrative pushed by Trump and his allies that the judicial process was unfair, NBC News reported.

"For the first time in American history, a former president that is a convicted felon is now seeking the office of the presidency," Biden said at the fundraising event.

"But as disturbing as that is, more damaging is the all-out assault Donald Trump is making on the American system of justice."

Trump was recently found guilty on 34 counts of falsifying business records in his New York hush money trial.

Biden did not hold back in his assessment, also calling Trump "unhinged."

"Something snapped in him when he lost in 2020. He can't accept he lost, and it is literally driving him crazy.

"Now he's running again. And he's not only obsessed with losing in 2020, he is clearly unhinged."

Commenting on Trump's attack on the judicial system, Biden added: "It's reckless and dangerous for anyone to say that's rigged just because they don't like the outcome.

"Here is what is becoming clearer and clearer every day," Biden said.

"The threat that Trump poses would be greater in a second term than it was in his first term. This isn't the same Trump who got elected in 2016. He's worse."

The President also told donors that he thinks Trump is running to keep his freedom, The Hill reported.

"Throughout this campaign Trump has made it clear he is running to exact for revenge.

"Now after his criminal convictions it's clear he's worried about preserving his freedoms."

Throughout the trial, Biden has tread carefully, avoiding direct commentary on the proceedings to sidestep accusations from the Trump camp that the case represents election interference by the Biden administration.

So, the Monday's remarks come as a sign of Biden's camp moving into an aggressive campaign strategy following Trump's conviction.

Trump has continuously denounced the verdict and the legal process.

Outside Trump Tower on Friday, Trump called the trial a "scam" and accused the Biden administration of orchestrating the proceedings, saying, "This is all done by Biden and his people. This is done by Washington."