NEW YORK - Homelessness, family strains and psychological problems among returning veterans of the Iraq and Afghanistan wars will persist in the U.S. for generations to come, the top U.S. military officer said Thursday.

"This is not a 10-year problem. It is a 50- or 60- or 70-year problem," Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, told a lunchtime audience at the Hudson Union Society, a group that promotes nonpartisan debate.

Mullen said he was particularly disturbed by the emergence of homelessness as a problem among war veterans.

"I have started to meet with, in veterans hospitals, homeless veterans" of the wars in Iraq and Afghanistan, he said. "And they are every bit as homeless and every bit as tragic as any homeless vet we've ever had. We as a country should not allow that to happen."

At a White House news conference last week, President Barack Obama said that some of the funding increases in his proposed budget for veterans affairs are directed at alleviating the problem of homelessness among veterans, which he said is a bigger problem, proportionally, than is homelessness in the rest of the American population.

Mullen said he also was worried by a rising number of suicides among U.S. military members.

"The trends are all in the wrong direction," he said, adding that "we're just at the beginning of understanding" how to deal with the psychological wounds and scars that military members incur during combat service.

"I believe the cumulative effects of these deployments, the pressure that so many are under, the impact of what ... mostly our soldiers and Marines have been through" on the battlefield "in our eighth year of war has a lot to do with" the suicide and other stress-related problems that are plaguing the military and their families, he said.

Mullen said the military has added hundreds of mental health professionals to help with the problem, yet "we're struggling with respect to that." Another aspect of the problem, he added, is the impact on children, who can suffer severely from the extended and repeated absence of a mother or father going off to war.

In a wide-ranging question-and-answer session with his audience, Mullen also said he was "reasonably comfortable" that Pakistan's nuclear weapons are secure amid a rising tide of insurgent violence aimed at the government.

"We have invested in that (effort), they've taken significant steps in recent years, so I'm comfortable," he said. "My biggest concern is that if Pakistan gets to a point where it implodes, you've got a country that could be an Islamist, theocratic country with nuclear weapons which could both use them and proliferate them. One of our goals is to make sure that doesn't happen."

He also explicitly linked the Pakistani military's intelligence arm, the Inter-Services Intelligence, to elements of the insurgency inside Pakistan, a connection that others have said helps empower the Taliban and other extremist groups.

"They've got an intelligence organization that must, in my view, change its strategic approach and be completely disconnected from the insurgents. And they're not right now," he said.

The role of Pakistani intelligence was discussed Wednesday at a Senate Armed Services Committee hearing in which Army Gen. David Petraeus, the top commander of U.S. forces in the Middle East and in Afghanistan, said there have been cases where Pakistani intelligence warned the insurgents of impending U.S. or Pakistani military strikes against them.

Petraeus called those episodes troubling. He said he and Mullen have raised the problem directly with the chief of Pakistani intelligence, Lt. Gen. Ahmed Shuja Pasha.