ST. PAUL, Minn. - Republican Norm Coleman has asked federal authorities to investigate how financial data for at least 4,700 Minnesota Senate campaign donors was breached and posted on the Internet.

Coleman campaign manager Cullen Sheehan mentioned the investigation in an e-mail sent to supporters Wednesday. It was in response to cryptic warnings many got the night before informing them of the possible leak of credit card information connected to their contributions.

"Let me be very clear: At this point, we don't know if last evening's email is a political dirty trick or what the objective is of the person who sent the email," Sheehan wrote. "What we do know, however, is that there is a strong likelihood that these individuals have found a way to breach private and confidential information."

The disclosure comes at a bad time for Coleman. He continues to solicit money to pay bills from his lawsuit challenging Democrat Al Franken's 225-vote lead following a statewide recount from their Nov. 4 race. A special court is nearing the end of a lengthy trial, but costly appeals could follow.

Sheehan said the campaign became aware of a possible security breach in January, but a probe then found that no unauthorized party had accessed the confidential information.

The e-mails that prompted Sheehan's message suggested donor credit card information was floating around the Internet. Tuesday night's warning under the subject line "Norm Coleman leak" came from a "Wikileaks Press Office" account.

"Your name, address and other details appear on a membership list leaked to us from the Norm Coleman Senate campaign," the group's e-mail said.

The warning said the sensitive information has been circulated out of public view. A follow-up e-mail linked to a spreadsheet showing details of the breached data — names, addresses, phone numbers, donation amounts, partial card numbers and security codes. The sheet contains information for 4,715 donors.

The group's Web site claims to have details for 51,641 Coleman contacts, but most of the data in "Senator Norm Coleman's big black book" is locked. A Washington-based phone number for the group prompts only a busy signal.

Wikileaks casts itself as an outlet for "untraceable mass document leaking and analysis," with a focus on exposing oppressive regimes worldwide and unethical behavior in corporations and government.

The Coleman campaign e-mail advised donors to contact their credit card company and cancel the card at issue.

"All of our donors and supporters should be assured that our campaign will work with all appropriate federal and state law enforcement agencies to take all appropriate legal action to identify the individual or individuals who may be involved in this matter and to pursue all appropriate legal action against them," Sheehan concluded.