Former Vice President Joe Biden will announce Thursday that he is running for president, multiple news outlets are reporting.

According to the Washington Post, the Delaware Democrat plans to make his candidacy official in an online campaign video Thursday morning, "a source close to him" said. A fundraiser for Biden, who is originally from Scranton, Pennsylvania, also is scheduled that evening in Philadelphia, Politico reported.

On Monday, Biden, 76, will make an appearance at a Pittsburgh union hall for his first campaign event, NBC News reported.

Biden, who served in the U.S. Senate from 1973 to 2009, unsuccessfully sought the Democratic nomination for president in 1988 and 2008. This time, he joins a packed field of 20 Democratic candidates vying to take on Republican President Donald Trump.

>> Read more trending news

Biden consistently has performed well in recent polls. In a national survey of Democrats released by Monmouth University this week, Biden led the field with 27% support, The Hill reported. He's also leading the Democratic pack in the RealClearPolitics polling average, with 29% support.

But the Monmouth poll found that Biden's favorability rating dropped from 76% in March to to 72% this month, according to The Hill. The drop came as multiple women came forward to accuse him of inappropriate contact.

"I will be more mindful and respectful of people's personal space, and that's a good thing, that's a good thing," he said earlier this month. "I've worked my whole life to empower women. I've worked my whole life to prevent abuse, I've written, and so the idea that I can't adjust to the fact that personal space is important – more important than it's ever been – is just not thinkable. I will. I will."

Read more here.