Updated

At the behest of CBS, an adviser to John Kerry said Monday he talked to a central figure in the controversy over President Bush's National Guard service shortly before disputed documents were released. The White House accused Kerry's campaign of fanning the controversy over Bush's military service.

Joe Lockhart (search) denied any connection between the presidential campaign and the papers. Lockhart, the second Kerry ally to confirm contact with retired Texas National Guard officer Bill Burkett (search), said he made the call at the suggestion of CBS producer Mary Mapes (search).

"He had some advice on how to deal with the Vietnam issue and the Swift boat" allegations, Lockhart said, referring to GOP-fueled accusations that Kerry exaggerated his Vietnam War record. "He said these guys play tough and we have to put the Vietnam experience into context and have Kerry talk about it more."

The White House called the exchange evidence of coordination between the Kerry campaign and Burkett.

"The fact that CBS News and a high-level adviser to the Kerry campaign coordinated a personal attack on President Bush is a stunning and deeply troubling development," said White House communications director Dan Bartlett. He urged Kerry to hold accountable anybody involved in helping CBS obtain the documents.

Lockhart denied any involvement. "Bartlett is wrong," he said later Monday.

Earlier, Lockhart said he thanked Burkett for his advice after a three- to four-minute call, and that he does not recall talking to Burkett about Bush's Guard records. "It's baseless to say the Kerry campaign had anything to do with this," he said.

Later, Lockhart said he was sure he had not talked to Burkett about the Guard documents.

CBS News apologized Monday for a "mistake in judgment" in its story questioning Bush's Guard service, claiming it was misled by the source of documents that several experts have dismissed as fakes. The network said an independent panel would look at its reporting about the memos.

CBS News spokeswoman Kelli Edwards said Mapes had declined to comment.

"This is an example of the kind of thing that the independent panel that will be named in a few days will look into. When that review is complete, we will comment," Edwards said.

Burkett admitted this weekend to CBS that he lied about obtaining the documents from another former National Guard member, the network said. CBS hasn't been able to conclusively tell how he got them, or even whether they're fakes.

Kerry ally Max Cleland, a former Georgia senator, also said he had a brief conversation last month with Burkett, who told him he had information about Bush to counter charges against Kerry's Vietnam War service. Cleland said he gave Burkett's name and phone number to the campaign's research department.

Kerry spokesman David Ginsberg said nobody in the campaign's research department followed up on Burkett's offer of information.

Lockhart said Mapes asked him the weekend before the story broke to call Burkett. "She basically said there's a guy who is being helpful on the story who wants to talk to you," Lockhart said, adding that it was common knowledge that CBS was working on a story raising questions about Bush's Guard service. Mapes told him there were some records "that might move the story forward. She didn't tell me what they said."