Joe Biden
Joe Biden has decided not to run in 2016 presidential electionsREUTERS/Yuri Gripas

US vice president Joe Biden has announced that he will not run for president in the 2016 presidential elections, citing his grieving process over the death of his son Beau earlier this year.

"I've concluded that the window for mounting a credible presidential campaign has closed," he said in a public statement, flanked by his wife and president Barack Obama, from the Rose Garden. The vice president added that even though he is not running he "will not be silent" and will "speak out clearly and forcefully."

Biden said: "I intend to speak out clearly and forcefully on where we stand as a party and where we need to go as a nation."

The 72-year-old politician ran previously in 1988 and 2008 and rumours said he believed he had an opportunity against the other candidates – Hillary Clinton, Martin O'Malley, Bernie Sanders, Jim Webb and Lincoln Chafee.

In a remark directed at Clinton, Biden repeated that it was "petty" to perceive Republicans as enemies. "I believe that we have to end the divisive partisan politics that is ripping this country apart, and I think we can," the vice president said.

"It's mean spirited, it's petty, and it's gone on for much too long. I don't believe, like some do, that it's naive to talk to Republicans. I don't think we should look at Republicans as our enemies. They are our opposition. They're not our enemies."

He added: "For the sake of the country, we have to work together." Following Biden's announcement, presidential candidates for 2016 sent messages of support to him. Republican presidential candidate said he would rather face Clinton as "her record is so bad".