US Vice President Joe Biden announced Wednesday he will not run for the White House in 2016, removing a potential obstacle to frontrunner Hillary Clinton's path to the Democratic presidential nomination.

"I believe we're out of time, the time necessary to mount a winning campaign for the nomination," Biden said in the White House Rose Garden with President Barack Obama and his wife Jill at his side.

"While I am not going to be a candidate, I will speak out clearly and forcefully as to where we stand as a party and where we need to go as a nation."