WASHINGTON (AP) Two congressmen say a classified Pentagon report on former National Security Agency systems analyst Edward Snowden asserts that most of the documents he took concerned current military operations.

"The vast majority of the material was related to the Defense Department, and our military services," not NSA operations, House Intelligence Chairman Mike Rogers said in an interview Thursday.

"Clearly, given the scope and the types of information, I have concerns about operations that would be ongoing in Afghanistan," Rogers said, as well other ongoing military operations.

The Michigan Republican and ranking committee member C.A. Dutch Ruppersberger, D-Md., said Snowden tipped off U.S. enemies to spying methods used to defend the country, and potentially jeopardized U.S. troops overseas.

They said the classified report by the Defense Intelligence Agency found that Snowden stole approximately 1.7 million intelligence files that "concern vital operations of the U.S. Army, Navy, Marine Corps, and Air Force."

Quoting the report, the lawmakers say the disclosures have already tipped off U.S. adversaries to U.S. defense methods, and hurt U.S. allies helping with counterterrorism, cybercrime, trafficking, and stopping weapons of mass destruction. They offered no specifics and none of the documents that have been published so far through Snowden associate Glenn Greenwald appeared to have dealt with current military operations.

Director of National Intelligence spokesman Michael Birmingham said intelligence officials are continuing to assess damage from the material Snowden took when he left the country in June 2013. "We've been clear that these leaks have been unnecessarily and extremely damaging," he said in a statement Thursday.

"As a result of these disclosures, terrorists and their support networks, now have a better understanding of our collection methods and, make no mistake about it, they are taking countermeasures," he said.