ABC's Imtiyaz Delawala and Ben Bell report…

Defense Secretary Chuck Hagel said he supports embattled Veterans Affairs Secretary Eric Shinseki, but called allegations of misconduct at a Phoenix veterans medical center that may have led to the death of veterans "outrageous."

"There is no one who understands accountability more than General Shinseki," Hagel told ABC's Martha Raddatz on "This Week" Sunday. "I do support General Shinseki… But there's no margin here. If this, in fact, or any variation of this, occurred, all the way along the chain, accountability is going to have to be upheld here… because we can never let this kind of outrage - if all of this is true - stand in this country."

The House Veterans Affairs Committee issued a subpoena for documents to the Veterans Affairs Department over allegations of severe misconduct at a Phoenix veterans hospital, including reports that the hospital's alternative waiting list may have resulted in 40 U.S. veterans dying while waiting for treatment. Shinseki has also opened an internal investigation and the agency announced Thursday that it will conduct face-to-face visits to clinics at every VA hospital to look into wrongful deaths.

Hagel agreed with calls to investigate the misconduct. "I think it's very appropriate that the Congress needs to take a look," Hagel said. "If these charges are true then it is outrageous."

While Hagel agreed that the average wait time at VA facilities of five months is "not good enough," he said that the problem has been long-standing, noting his own speeches as a senator in which he warned about the impacts of the wars in Iraq and Afghanistan in overloading the care system for veterans.

"I don't think it just started with General Shinseki's term at the VA," Hagel said. "This is something that should have been looked at years and years ago. So, yes, we - we missed it."

Hagel: Will Be 'Very Difficult' to Find Kidnapped Nigerian Girls

During the interview, Hagel told Raddatz that locating the girls kidnapped by the Islamist group Boko Haram - which has sparked international outrage and the viral campaign "Bring Back Our Girls" - would be difficult given the physical makeup of Nigeria.

"It's going to be very difficult. It's a vast country… So this is not going to be an easy task. But we're going to bring to bear every asset we can possibly use to help the Nigerian government," said Hagel, who noted that U.S. support teams are already on the ground in Nigeria.

Hagel would not rule out sending U.S. special operations forces to Nigeria if the country made the request, but said there are no plans to do so.

"I think you look at everything," Hagel said. "There's no intention, at this point, to be putting any American boots on the ground."

Hagel on Cyber Threat to Drones

Hagel told Raddatz the U.S. is paying close attention to the issue of cyber security, including increasing the budget for cyber defense, but worries that not enough people are.

When asked about the ongoing threat of cyber terrorism, the Defense secretary would not say he is confident that U.S weapons systems, including drones, could not be hacked.

"I'm not confident of anything in this business. You can't be. You have to anticipate every threat, every challenge," Hagel said. "But the fact is, Martha, it is a as dangerous a threat that we are dealing with, the world deals with, especially the United States, as any one threat. It's quiet. It's insidious. It's deadly."

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