Biden says he's 'not the only one who can defeat' Trump

President Joe Biden said Wednesday that he didn't think he was the only Democrat who could prevail over former President Donald Trump next year but that "I will defeat him" — a day after he suggested he wouldn't be running for re-election had Trump stayed out.

Biden was delivering remarks urging Congress to pass his national security package when he responded to a reporter's question about whether he thought another Democrat could defeat Trump, the Republican presidential front-runner.

"Probably 50 of them," Biden said.

“No, I’m not the only one who can defeat him, but I will defeat him,” he added.

On Tuesday, Biden said that his re-election campaign was prompted in part by Trump’s decision to run for president again and that it was an effort to block his predecessor from reclaiming the White House.

“If Trump wasn’t running, I’m not sure I’d be running,” Biden said at a campaign event in Boston, adding that he “cannot let him win.”

Biden's decision to run for re-election has prompted some criticism from within his own party, some of it from Rep. Dean Phillips of Minnesota, his primary challenger, who argues that Biden, 81, should pass the torch to a younger generation.

Shortly after Phillips launched his presidential campaign in October, he suggested Biden couldn't win in the coming general election.

“Right now, if this election was held today, President Biden would lose, and it is an existential threat to the future of the United States of America. That will not happen under my watch,” Phillips said in an interview on NBC's “Meet the Press” at the time.

This article was originally published on NBCNews.com