Colombo, April 26 -- Former US Vice President Joe Biden, in an online video Thursday, officially declared his candidacy for president in 2020, capping off weeks of intrigue and media speculation.

He enters a crowded field of Democratic contenders aiming to unseat President Trump -- nearly 32 years after he announced his first campaign for president. The campaign is Biden's third for the White House, having also unsuccessfully run in 1988 and 2008.

"The core values of this nation, our standing in the world, our very democracy, everything that has made America -- America -- is at stake. That's why today I'm announcing my candidacy for president of the United States," Biden tweeted early Thursday.

With the announcement, which followed mon...