WASHINGTON—The leak of tens of thousands of classified U.S. military documents on the Afghan war, while illegal, has little significance for policymaking, Sen. John Kerry said Tuesday.

Kerry, D-Mass., chairman of the Senate Foreign Relations Committee, said the documents posted on the Internet on Sunday revealed little that was not already known to U.S. officials.

"I think it's important not to overhype or get excessively excited about the meaning of those documents," Kerry said at the outset of a committee hearing on prospects for negotiating an end to the Afghan war.

He said the release was unlawful and could potentially endanger U.S. troops in Afghanistan.

But he also said the secret documents should be given little weight because in many cases they reflect raw intelligence, not carefully calibrated assessments of trends on the ground. Some of the documents, Kerry said, are "completely dismissible," but others are not.

Kerry disputed suggestions that the significance of the leak was on a par with The New York Times' publication in 1971 of the Pentagon Papers, a top-secret Pentagon study of the history of U.S. involvement in Vietnam.

"There is no relationship whatsoever to that event or to those documents," Kerry said. "In fact, these documents in many cases reflect a very different pattern of involvement by the U.S. government from that period of time."

The committee's ranking Republican, Dick Lugar of Indiana, made only a passing reference to the weekend's document leak in his opening remarks to the hearing. He said the records, "if they are credible, attest to the special difficulties involved" in stabilizing Afghanistan.

© Copyright 2010 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.