John Kerry (search) secured the endorsement of former presidential rival Dick Gephardt (search) on Thursday, a blockbuster embrace that paid immediate dividends for the Democratic front-runner's bid to rally organized labor behind his candidacy.

Kerry spokesman David Wade (searchsaid the Missouri lawmaker will give Kerry his backing on Friday in two blue-collar Michigan cities, Warren and Flint.

He confirmed the endorsement as two labor officials, speaking on condition of anonymity, said an alliance of labor groups formed by the Teamsters and more than a dozen industrial unions planned to endorse Kerry. The Alliance for Economic Justice made the decision after a morning meeting in Boston, where Kerry began his day, but must seek approval of their boards, which is expected in the next week.

A Democratic official, familiar with the talks, said Gephardt urged the group to back Kerry. The coalition was formed in the fall by unions that supported Gephardt after it became clear that some of the larger public and service sector unions did not want to give him a laborwide endorsement from the AFL-CIO. They include the steelworkers, laborers, machinists, ironworkers and others.

Kerry tightened his grip on the front-runner's title with back-to-back wins in Iowa and New Hampshire and victories in five of the seven states that voted Tuesday. Gephardt's backing caps a series of endorsements Thursday for Kerry, including Maine's governor, the two Michigan senators and former Senate majority leader George Mitchell, D-Maine.

Howard Dean, the front-runner just six weeks ago, is in danger of losing support from three major unions backing him -- the Services Employees International Union, the American Federation of State, County and Municipal Employees and the International Union of Painters and Allied Trades.

The three union presidents plan to talk Friday about how much -- and how much longer -- they're willing to keep their financial and political commitments to Dean. SEIU President Andy Stern is said to be behind Dean through the Feb. 17 Wisconsin primary, which Dean says is make-or-break, though his union's influence is relatively small in the state. AFSCME President Gerald McEntee is thought to be more anxious, two Democratic officials said.

Kerry's new labor endorsements won't be announced until at least next week. The union presidents wanted time to brief their members before making the endorsement public, the sources said.

Gephardt dropped out of the race last month after a fourth-place finish in the Iowa caucuses. He said then that he intended to support the party's nominee, but had no immediate plans to endorse any of the contenders.

The 14-term congressman gained the support of more than 20 unions with more than 5 million members. He failed in a bid to win the backing of the AFL-CIO, though, when Dean collected the support of SEIU and AFSCME, two of the labor federation's largest members.

Rival John Edwards, campaigning in Tennessee, called Gephardt a "wonderful man," but argued that "if you look at the history of endorsements in this campaign, they haven't had a lot of sway with voters, which is understandable. Voters make their own decisions."

Among former presidential candidates, only Carol Moseley Braun has endorsed, and she chose Dean.