HARRISBURG — Even though he carries endorsements from the loftiest echelons of the Democratic Party, Sen. Arlen Specter appears increasingly likely to face competition for his new party's nomination when he seeks a sixth term next year.

U.S. Rep. Joe Sestak, a retired Navy vice admiral from the Philadelphia suburbs, and state Rep. Bill Kortz, a former U.S. Steel manager from the Pittsburgh area, both say they plan to challenge Specter. Neither has formed a campaign committee to raise money.

Specter, 79, defected to the Democratic Party in April after more than four decades as a Republican. He said the Pennsylvania GOP had grown too conservative for him to survive a primary challenge from former Rep. Pat Toomey. President Barack Obama and Gov. Ed Rendell are among the Democratic leaders backing his re-election.

"We expect a tough fight ... and we're confident that whoever runs against us, we'll beat 'em," Specter's campaign spokesman, Christopher Nicholas, said of the primary still 10 months away.

Specter's campaign account totaled $6.7 million as of March 31, the most recent figure available, while Sestak's congressional campaign committee had half that much. Kortz said he plans to begin fundraising this month.

Sestak, 57, said he would probably form a committee around the time he announces.

Kortz, 54, is serving his second term in the Pennsylvania Legislature. Despite Specter's head start fundraising, Kortz said he believes he can be competitive.

"If I can get $2 million, I can beat him," he said.