Former Vice President Joe Biden Joe BidenBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Democratic groups using Bloomberg money to launch M in Spanish language ads in Florida Harris faces pivotal moment with Supreme Court battle MORE on Wednesday jokingly addressed the barrage of Twitter attacks President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE aimed at him earlier in the day.

"I understand the president has been tweeting about me this morning," Biden said at a campaign event in Iowa, followed by a laugh. "I wonder why the hell he’s doing that."

Here's video of @JoeBiden on Donald Trump's tweets from this AM that @MarcACaputo flagged earlier: "I understand the President has been tweeting about me this morning ... I wonder why in the hell he’s doing that." pic.twitter.com/DvgDBSjj9m — Marcus DiPaola (@marcusdipaola) May 1, 2019

ADVERTISEMENT

Trump in an early morning Twitter spree retweeted nearly 60 posts, most of which knocked Biden and his 2020 presidential campaign.

Trump "welcomed" Biden to the campaign trail last week, calling him "Sleepy Joe" in a post on Twitter.

Welcome to the race Sleepy Joe. I only hope you have the intelligence, long in doubt, to wage a successful primary campaign. It will be nasty - you will be dealing with people who truly have some very sick & demented ideas. But if you make it, I will see you at the Starting Gate! — Donald J. Trump (@realDonaldTrump) April 25, 2019

Trump has reportedly rebuffed advice to ignore Biden from his political advisers, who worry the president risks elevating the former vice president's profile, according to CNN.

Biden has shown a penchant for firing back at Trump, saying in a tweet earlier this week that he is "sick of this president badmouthing unions."

Biden is leading the Democratic field in several early polls.