Vice President Joe Biden
Vice President Joe BidenReuters

Vice President Joe Biden ended months of speculation on Wednesday with an announcement that he wouldn't seek the presidency, CNN reported.

With his wife, Jill, and President Barack Obama at his side in the White House Rose Garden, Biden said the window for a successful campaign "has closed," noting his family's grief following the death of his son, Beau.

The vice president sent a pointed warning to Democratic front-runner Hillary Clinton in his remarks, apparently rebuking her for her comment in last week's CNN Democratic debate that Republicans were her enemies.

"I believe that we have to end the divisive partisan politics that is ripping this country apart, and I think we can," said Biden, adding, "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."

"For the sake of the country, we have to work together," added Biden.

The Vice President stressed that "While I will not be a candidate, I will not be silent. I intend to speak out clearly and forcefully, to influence as much as I can where we stand as a party and where we need to go as a nation."

His announcement that he would not be running came following a report earlier in the week that Biden was inching closer towards announcing his intention to seek the Democratic nomination for president, and that his associates were setting up interviews for potential staff positions on a presidential campaign.

The reports followed a poll last week which found that almost half of American Democrats want Biden to challenge Clinton in the 2016 presidential race.

According to CNN, two looming political events may have affected the timing of Biden's announcement. On Thursday, Clinton appears before a Republican-led committee on Capitol Hill probing the deaths of four Americans in attacks on U.S. facilities in Benghazi, Libya, on September 11, 2012, when she was secretary of state. The vice president may not have wanted his decision to be seen as a judgment on her performance if it was made public after the hearing.

Democrats are also gathering this weekend at an important party dinner in Iowa -- a must stop for presidential candidates seeking the nomination and a Biden no-show would likely have severely hampered his chances in the state, noted the network.

Clinton had only praise for Biden, describing him in a Tweet on Wednesday as "a good friend and a great man. Today and always, inspired by his optimism and commitment to change the world for the better," she wrote. "She signed the Tweet "--H" signifying that she, and not a campaign aide, composed the message.

Besides Clinton, other Democratic candidates are Senator Bernie Sanders of Vermont, as well as former Maryland Governor Martin O’Malley, ex-Senator Jim Webb of Virginia and Lincoln Chaffee, a former governor of Rhode Island,

Clinton has been perceived as increasingly politically vulnerable as questions persist over her use of a private email server while she was secretary of state in the Obama administration..