Democratic National Committee Chairman Tim Kaine said Tuesday he is running for the U.S. Senate, leaving an opening at the central committee as the party prepares for President Obama's re-election bid.

"I'm running for the United States Senate because America has big challenges and I'm convinced that Virginia has answers to help strengthen our nation," the former Virginia governor said in an online video.

The video never mentions his tenure at the partisan DNC and he appeals to work across party lines.

"While we still have an awful lot of work to do to help Virginians who are struggling in tough times, I know that Washington can learn a few things from Virginia. When we attack common obstacles -- instead of each other -- we solve problems and get things done," Kaine said.

Kaine would enter the race to succeed Democratic Sen. Jim Webb, who announced he was retiring from office after just one term.

Kaine has mulled a Senate run in recent weeks and had given strong signs he would mount a Senate campaign.

His candidacy leaves an opening for a DNC chairman to oversee the central party as Obama heads toward a re-election bid. The DNC also would have to help the party defend a majority in the U.S. Senate and fight to reclaim power in the U.S. House.

Among those under consideration to replace Kaine at as Democratic National Committee chairman are former Ohio Gov. Ted Strickland, Florida Rep. Debbie Wasserman Schultz and Illinois Sen. Richard Durbin. Party officials are weighing who would be the best surrogate for the president as he embarks on his re-election campaign. Both Strickland and Wasserman Schultz hail from all-important presidential battlegrounds, while Durbin is a close confidant of the president.

Kaine, who won election as governor in 2005, was among the first elected officials to back Obama's primary bid. Obama named him the DNC post and has nudged Kaine toward a run. Last week, he said Kaine was "not just a leader for Virginia; he's a leader for America."

On the Republican side, two former governors are competing for the nomination. Republican George Allen, who lost the Senate seat to Webb in 2006 and was governor from 1994 to 1998, announced his candidacy earlier this year.

He faces opposition for the nomination from tea party activist Jamie Radtke.

Allen was a strong 2008 presidential contender until a series of blunders derailed his Senate race and Webb won by just 9,000 votes.