Former New Jersey Governor Chris Christie and a Republican presidential aspirant have called his fellow rival Indian-American Vivek Ramaswamy a guy who sounds like ChatGPT and described him as an "amateur" Barack Obama.

Christie, 60, on Wednesday, said this during the maiden Republican presidential debate against Ramaswamy, 38, the youngest of the GOP candidates on the stage in Milwaukee, Wisconsin, which was telecast live by Fox News and its affiliate channels.

Latest opinion polls show that Ramaswamy is now the second in lead after former US president Donald Trump. He did not participate in the debate that had eight aspirants on the stage.

“Hold on, I’ve had enough already tonight of a guy who sounds like ChatGPT,” Christie said launching the first of the series of attacks against Ramaswamy after he said that the climate change agenda is a hoax.

“He stands up here, and the last person in one of these debates, Brett, who stood in the middle of the stage and said, 'What's a skinny guy with an odd last name doing up here' was Barack Obama. And I'm afraid we're dealing with the same type of amateur tendencies tonight," Christie added.

Ramaswamy who in recent weeks has seen his popularity moving up the ladder against other GOP presidential aspirants was also attacked by former Vice President Mike Pence who called him a rookie.

“We don’t need to bring in a rookie,” Pence said, pointing towards Ramaswamy.

Even President Joe Biden appeared to react to Ramaswamy’s comment during the debate on climate change.

"Climate change is real, by the way," the president posted on X, formerly known as Twitter, soon after Ramaswamy described it as a hoax.

"I'm the only person on the stage who isn't bought and paid for so I can say this: The climate change agenda is a hoax. And the reality is the anti-carbon agenda is the wet blanket on our economy. And so the reality is more people are dying of bad climate change policies than they are of actual climate," Ramaswamy said.

Two Indian-Americans were on the Republican presidential debate stage, former South Carolina Governor Nikki Haley, the only woman in the race so far and entrepreneur-turned-politician Ramaswamy, the youngest of them on the stage.

“You've got people on this stage that won't even talk about issues like Social Security and Medicare. I mean, Vivek, you recently said the president can't do everything. Well, I got news for you, Vivek. I've been in the hallway. I've been in the West Wing. A president of the United States has to confront every crisis facing America," Pence said, referring to Ramaswamy.

"This isn't that complicated, guys," Ramaswamy responded.

"Unlock American energy, drill, frack, burn coal, embrace nuclear. Put people back to work by no longer paying them more to stay at home. Reform the US Fed, stabilise the US dollar and go to war. The only war that I will declare as US president will be the war on the federal administrative state that is the source of those toxic regulations, acting like a wet blanket on the economy," said the young Indian-American.

Earlier, Ramaswamy described himself as a skinny guy with a funny name.

“Let me just address the question that is on everybody's mind at home tonight. Who the heck is this skinny guy with a funny last name, and what the heck is he doing in the middle of this debate stage?" he said with a smile on his face.

"I'll tell you, I'm not a politician. You're right about that. I'm an entrepreneur. My parents came to this country with no money 40 years ago. I have gone on to found multi-billion dollar companies. That is the American dream. And I am genuinely worried that that American dream will not exist for our two sons and their generation unless we do something about it," Ramaswamy said.

During the debate, Ramaswamy was continuously being attacked and pointed out in person by Pence and Christie.

Meanwhile, Indian-American Congressman Ro Khanna said that former US President Obama must be smiling that a 38-year-old son (Ramaswamy) of Hindu immigrants running to the right of Trump is "cribbing from him".

"Somewhere @BarackObama must be smiling that a 38-year-old son of Hindu immigrants running to the right of Trump is cribbing from him! Obama’s vision for a multiracial democracy is seeping into our politics despite the intense backlash. A slow but satisfying vindication," Indian-American Congressman Ro Khanna posted on X.

A second-generation Indian-American, Ramaswamy founded Roivant Sciences in 2014 and led the largest biotech IPOs of 2015 and 2016, eventually culminating in successful clinical trials in multiple disease areas that led to FDA-approved products, according to his bio.

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