Former US president and Republican presidential candidate Donald Trump on Wednesday said Vice President Kamala Harris is “unfit to rule” and described here a radical left lunatic.

Trump, 78, launched a scathing attack on his Democratic rival, as he took the stage for the first time to address an election rally after Harris became the presumptive nominee.

Over the weekend, President Joe Biden, 81, announced that he was dropping out of the race and named Harris as his successor.

Harris, 59, is now the presumptive Democratic nominee and she was officially announced as the party’s presidential candidate at its Democratic National Convention in August.

“For three and a half years, Lyin’ Kamala Harris has been the ultra-liberal driving force behind every single Biden catastrophe. She is a radical left lunatic who will destroy our country if she ever gets the chance to get into office. We're not going to let that happen,” Trump said as he unleashed a torrent of attack against the vice president.

“I was supposed to be nice. They say something happened to me when I got shot. I became nice. And when you're dealing with these people, they're very dangerous people. When you're dealing with them, you can't be too nice. You really can't be. So if you don't mind, I'm not going to be nice. Is that okay?” he asked his supporters amidst huge applause from the audience.

“Kamala Harris is the most liberal elected politician in American history. She's an ultra-liberal politician. She's absolutely terrible. She's, more liberal than Bernie Sanders,” he said. “If she ever got in, she'd destroy this country so fast. She was the border czar, but she never went to the border,” he alleged.

“She was appointed by this horrible president, this horrible guy. How this guy got to be president in his basement. He stayed in his basement. And we did a lot better the second time than we did the first. How this guy got to be president, what they've done to this country in three and a half years, and we're going to turn it around. But what they've done to our country is unthinkable,” he alleged.

Trump told his cheering supporters that Harris' lies.

“If Kamala will lie to you so brazenly about Joe Biden's mental incapacity, then she will lie to you about anything. She can never, ever be trusted. She can't be trusted. Just like crooked Joe Biden, Kamala Harris is unfit to lead. She's unfit to lead. She'll destroy our country in a year. This country will be destroyed,” he said.

“A vote for Kamala is a vote for four more years of dishonesty, incompetence, weakness and failure,” Trump said. In his maiden speech after Harris replacing Biden as the Democratic presidential nominee, Trump alleged everything Kamala touches turns into a total disaster. He mentioned Harris as many as 45 times in his speech.

“When Kamala Harris was sent to Europe to deter Russia from attacking Ukraine, how did that work out? Russia answered by launching the invasion just five days after she left. Putin laughed at her like she was nothing. She is nothing. She's so bad for us. Everything Kamala touches turns into a total disaster. She's destroyed San Francisco with the policies,” Trump said.

“She'll destroy our country if she's elected. So we won't let her be elected. We can't let that happen. Unbelievably, despite all of the damage she's caused, radical, liberal Kamala Harris now wants a promotion to deliver four more years of chaos. We've had the worst four years,” he said.

“This November, the American people are going to tell her, no thanks, Kamala. You've done a terrible job. You've been terrible at everything you've done. You're ultra-liberal. We don't want you here. We don't want you anywhere. Kamala, you're fired. Get out of here. You're fired,” Trump said.

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.