The Pentagon failed to disclose clandestine cyber activities in a classified report on secret military actions that goes to Congress, according to a Senate document that provides a public peek at oversight concerns surrounding the government's computer war capabilities.

A brief written exchange between Senate questioners and the Pentagon's assistant secretary for special operations, Michael Vickers, underscores unresolved questions about how and when the Pentagon conducts cyber warfare, and about the guidelines for military action in the event of a computer-based attack on the U.S.

The U.S. military's use of offensive cyber warfare has only rarely been disclosed, the most well-known instance being the electronic jamming of Iraqi military and communications networks just before the lightning strike against Saddam Hussein's army in 2003. But Pentagon officials have been clear that cyber espionage and attacks from well-funded nations or terror groups are the biggest threats to military networks, including critical battlefield communications.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, told reporters Wednesday that the cyber threat from China is significant and that the Defense Department needs to focus more on cyber warfare. The Pentagon has made a lot of changes to deal with the threat, he said in remarks at the Foreign Press Center, but added that the U.S. has to "come to a place where, again, those threats are diminished, if not eliminated."

The growing threat has been evident in recent global clashes including the Internet blitz against Georgian government sites just before the Russians invaded in 2008 and the Chinese government's reported efforts to develop computer viruses to attack enemy networks. The Pentagon created Cyber Command to better deal with the threats, but has yet to clearly define the parameters of its offensive and defensive cyber operations.

Nowhere does the brief Senate exchange obtained by The Associated Press detail the cyber activities that were not disclosed. But cyber experts suggest they may have involved secret operations against insurgents in Iraq and Afghanistan, and could possibly include other hotspots such as Yemen or Somalia.

The exchange emerged in a question posed to the Vickers, who has been nominated as undersecretary of defense for intelligence.

The Senate Armed Services Committee voiced concerns that cyber activities were not included in the quarterly report on clandestine activities. But Vickers, in his answer, suggested that such emerging high-tech operations are not specifically listed in the law — a further indication that cyber oversight is still a murky work in progress for the Obama administration.

Vickers told the committee that the requirement specifically calls for clandestine human intelligence activity. But if confirmed, he said, he would review the reporting requirements and support expanding the information included in the report.

"It would be my intent, if confirmed, to fully comply with that responsibility, to include cyber activities," he said.

The exchange was included in 33 pages of Senate questions and answers from Vickers in preparation for his nomination hearing. No hearing date has been set.

Pentagon spokesman Cmdr. Bob Mehal declined to discuss the clandestine activities report or the answers Vickers submitted to the panel, because the report is classified, and Vickers' submission has not been made public.

James Lewis, a cyber security expert and longtime consultant for the government on such high-tech related issues, said it is likely the committee complaint referred to ongoing military cyber activities in the Iraq and Afghanistan wars, although there also could be similar efforts in Yemen or other countries where the U.S. is supporting counterinsurgency operations.

Lewis said there have been longstanding tensions between the congressional committees and the various military and intelligence agencies over how much sensitive information is given to lawmakers, as well as historical turf battles that have played out repeatedly between the various panels with overlapping oversight of military and intelligence.

The oblique exchange between Vickers and the Senate panel also highlight congressional efforts to map out strict oversight and command and control guidelines for the military's shadowy cyber role.

"Congress members and staff always feel they should be getting much more info about clandestine operations than they get," said Lewis. He added that while there are times when it's better to strictly control access to some classified information, there is still "a legitimate need for oversight since such clandestine activity can have political consequences."

The exchanges between Vickers and the Senate panel also cover a wide range of other intelligence issues.

If confirmed, Vickers said, his big challenge would be the continuing struggle to meet the military's "unmet demand" for intelligence as the U.S. fights two wars and works to dismantle terrorist networks, including those in Yemen and Somalia.

Asked whether the intelligence community has devoted enough counterterrorism resources to Yemen and Somalia, Vickers said the military needs more intelligence and special operations forces with language and cultural expertise.

He added that he would like to see funding increase from $40 million to $50 million for counterterror operations in Iraq and Afghanistan and efforts to train other nations' forces. Such training is being done in a number of countries including Yemen and Pakistan.

Vickers also offered a sharp condemnation of recent leaks of classified data. He did not specifically cite the more than a quarter-million diplomatic records obtained by WikiLeaks, but he said unauthorized disclosures are among the most serious problems he would face.

"The spate of unauthorized disclosures of very sensitive information places our forces, our military operations and our foreign relations at risk," he said.

Vickers, a former Green Beret, has had a long and storied career, including his engineering the clandestine arming of Afghan rebels who drove the Soviet Union out of their country in the 1980s. His role in one of the largest covert actions in the CIA history was chronicled in the 2003 book "Charlie Wilson's War," which became a film in 2007.