The Pentagon says the documents leaked by the WikiLeaks website in July do not jeopardize any U.S. intelligence or sensitive military operations.
In an Aug. 16 letter released to NPR, Defense Secretary Robert Gates responded to questions about the WikiLeaks documents raised by Sen. Carl Levin (D-MI), chairman of the Senate Armed Services Committee.
Gates said an initial Pentagon review showed the documents focused mostly on day-to-day military operations and did not reveal any significant national intelligence secrets.
The letter confirmed that the documents name Afghan civilians who may have ties to the U.S. military operation, and the Taliban threats made against some of those named. That, Gates said, is something that could pose a risk to U.S. national security interests.
WikiLeaks, a self-described whistle-blower website, said it plans to release thousands of other documents. Gates, in the letter, said the Pentagon is developing a plan to deal with that possibility.
The website is believed to be preparing to release classified Pentagon documents on the Iraq war as early as Sunday.
Questions persist about whether the disclosure of nearly 77,000 secret documents undermined U.S. officials' ability to maintain the allegiance of allies and people from other countries who take risks to cooperate with the U.S.
"The mere fact of the disclosure erodes confidence in the ability of the military to keep secrets," said Steven Aftergood, whose Secrecy News blog tracks trends in government openness. "And that can have subtle but real effects on recruitment of sources and on maintenance of relationships with individuals and with other security services."
Military investigators say Army Pfc. Bradley Manning, who served as an intelligence specialist in Baghdad, is a person of interest in the investigation into who provided the Afghan war logs to WikiLeaks.
NPR's Rachel Martin contributed to this report, which also includes material from The Associated Press