NEW YORK/ WASHINGTON: Former US presidents Barack Obama and Bill Clinton have jumped to the aid of incumbent Joe Biden in the election campaign.

The three Democrats appeared together at a major fundraising event in New York on Thursday evening. The event at Radio City Music Hall in Manhattan also featured several music stars. Biden's campaign team said it raised more than US$26 million, reported German news agency (dpa).

The campaign show was accompanied by protests against the US government's Middle East policy, with hecklers interrupting the prominent Democrats on stage several times, and others demonstrating outside.

Several thousand people attended the event, having paid between US$225 and half a million dollars for a ticket. Former president Obama flew from Washington to New York in the government aircraft Air Force One with his former vice president Biden. Clinton made his own way to the event. The three sat together on stage for a moderated panel discussion, talking about democracy, life in the White House, international conflicts and difficult decisions as president.

Obama and Clinton praised Biden's work. He, in turn, attacked the Republican former president Donald Trump, who wants to run against the incumbent in November's election. Biden warned that his rival denies climate change, is on good terms with autocrats around the world and wants to curtail fundamental rights.

Obama said that voters are faced with the question of who is really interested in their concerns and cares about them. “I’m pretty sure the other guy doesn’t,“ he said of Trump. But on Biden, he said, “this guy does”. -Bernama