The Specter campaign misfired in an early shot against likely challenger Pat Toomey, but the incumbent's team is still blasting away.

Facing criticism over an inaccuracy in an anti-Toomey cable television ad, the Specter campaign has revised its wording. The ad assails the former congressman over his record as a financial executive.

Originally, the unusually early ad said of Mr. Toomey, "As a Wall Street trader, he sold risky derivatives called credit default swaps."

Mr. Toomey responded that credit default swaps, which earned notoriety as they exacerbated the losses of financial institutions in the current economic crisis, had not even been invented yet when he was an investment banker from 1984 to 1991.

Chris Nicholas, Mr. Specter's campaign manager, at first defended the wording of the ad. Yesterday, however, the campaign altered the commercial to say that Mr. Toomey "sold risky derivatives and swaps."

"We don't want the campaign to get bogged down in a debate over terminology," Mr. Nicholas said in response to a question about the change.

Hoping to keep the spotlight on Mr. Toomey's resume at a time of widespread anger at Wall Street, Mr. Specter sent a letter yesterday calling on his anticipated opponent, who is the president of the conservative lobbying group, the Club for Growth, to disclose any contributors that had received federal funds under the controversial financial bailout legislation enacted in October.

Mr. Toomey has criticized the Specter vote in favor of the October measure, the Troubled Assets Relief Program, known as TARP, and has been even more caustic about the incumbent's vote in favor of the Obama administration's massive stimulus package. He has said Mr. Specter's October vote was a catalyst for his apparent decision to challenge the veteran senator in next year's primary.

"Given the Wall Street background of your members, it seems clear that many of them would have received TARP monies,'' Mr. Specter wrote on campaign stationery.

Mr. Toomey did not immediately respond to a request for comment on the Specter demand.

Both the extraordinarily early ad and the new demand for information reflect the Specter campaign's aggressive stance toward Mr. Toomey, who has yet to officially declare his candidacy.

Mr. Toomey, continuing the criticisms he voiced in the 2004 primary when he nearly ousted the veteran incumbent, has been similarly unrelenting in portraying Mr. Specter as a liberal out of touch with his party's conservative base.

Mr. Toomey has said repeatedly that he is likely to enter the race against Specter.

Those who have declared themselves as candidates include Peg Luksik, a conservative activist, and Larry Murphy, a retired Air Force officer who lost a GOP primary race to Mr. Specter in 1998.