American officials from the president down tried Tuesday to downplay the leak of tens of thousands of documents about the war in Afghanistan, a disclosure experts are calling the biggest leak since the Pentagon Papers about Vietnam.

Pentagon officials have not found anything top-secret among the documents, a Defense Department spokesman said Tuesday.

“From what we have seen so far, the documents are at the ‘secret’ level,” Col. David Lapan said. That’s not a very high level of classification.

Lapan emphasized that the Pentagon has not looked at all of the more than 75,000 documents published on WikiLeaks.org on Sunday.

President Barack Obama said Tuesday that he is “concerned about the disclosure of sensitive information” about the U.S. mission in Afghanistan but asserted that the documents don’t shed much new light on the issue.

Senate Foreign Relations Committee Chairman John Kerry, D-Massachusetts, said Tuesday that the importance of the leak should not be overstated.

“I think it’s important not to overhype or get excessively excited about the meaning of those documents,” Kerry told the committee.

But, he said, the leak “breaks the law, and equally importantly, it compromises the efforts of our troops, potentially, in the field and has the potential of putting people in harm’s way,” he said.

The top-ranking U.S. military officer, Adm. Michael Mullen, said he was “appalled” by the leak but questioned the current significance of the documents, which date from 2004 to 2009.

(Source: CNN)