Updated

Sen. Arlen Specter said Sunday he did not attempt to clear the field in the Pennsylvania Democratic primary after his potential opponent claimed members of the state's political establishment tried to lure him out of the race.

"I'm ready to take on all comers," Specter, who switched his party affiliation from Republican to Democrat in April, told "FOX News Sunday."

He responded after Rep. Joe Sestak, D-Pa., who is expected to mount a primary challenge against Specter, told FOX News that people in the Pennsylvania "establishment" contacted him and asked him not to run against Specter. He said he's disappointed that party leaders are trying to "anoint" the senator, calling Specter "self-serving" and "more concerned about his job" than his state.

Specter rejected that suggestion Sunday.

"It's a free society. I didn't ask that the field be cleared," Specter said. "There was no discussion of that. Everybody ought to run if he or she wants to run."

Asked if he's certain he can beat Sestak, Specter said, "there's no such thing as certainty" in a political campaign.

A recent poll, though, showed Sestak trailing Specter by nearly 30 points in a Democratic primary match-up.