The US election is heating up to be a feisty campaign, with shots being fired on both sides.
Republican candidate Donald Trump has called rival Democrat and current US President Joe Biden a "total moron", while Biden said Trump should have injected himself with bleach.
The scathing comments come less than six months out from the November 5 election.
Trump held a massive rally in Wildwood, New Jersey on Saturday (local time) where he avoided any legal issues amid his ongoing court trial by focusing on Biden.
"You could take the 10 worst presidents in the history of our country, and add them up... and they haven't done the damage to our country that this total moron has done," he told a cheering crowd, according to the New York Post.
"He's a fool, he's not a smart man. He never was," the 77-year-old doubled down.
"He was considered stupid. I talk about him differently now because now, the gloves are off. He's a bad guy… he's the worst president ever, of any country. The whole world is laughing at him, he's a fool."
Trump also blamed Biden for his legal troubles, saying his actions were "done in third world countries" but "it's not done in the United States of America".
The nasty comments come after Biden also fired shots at the former US president.
The 81-year-old joked on Friday (local time) that he wished Trump had injected himself with a little bleach - resurrecting one of Trump's bizarre claims that disinfectant could be an effective treatment for COVID-19 in the early days of the pandemic.
"Remember him saying the best thing to do is just inject a little bleach in your arm? That's what he said. And he meant it. I wish he had done a little bit himself," Biden said at a fundraising event south of San Francisco for his re-election campaign, according to Reuters.
It's not the first time Biden's poked fun at the bleach comment, though. Speaking from Washington on April 24, he said that if Trump had injected himself "it all went to his hair".
