JEFFREY BROWN: It happened again today—twice, in fact. Afghan forces turned their guns on international troops.

In Farah province, a new police recruit shot and killed two Americans just minutes after receiving his gun to begin training. And in Kandahar province, an Afghan soldier wounded two coalition troops. There was no word on their nationalities.

That made seven incidents in two weeks involving shooters in Afghan army or police uniforms, so-called green-on-blue attacks. In all, there have been 29 such attacks so far in 2012, nearly double the figure from last year. At least 37 foreign troops have been killed, including 21 Americans.

The toll for all of last year was 35 coalition deaths; 24 were Americans.

For more, we turn to Mark Thompson, "TIME" magazine's Pentagon reporter.

Mark, start with the latest incidents. The one in Farah, for example, do we know anything more of the motive or who the person was?

MARK THOMPSON, "TIME": Well, we know what may have been a new recruit, but he was either 60 or 70 years old.

He was a farmer. This was the local police force, not the national police force. He had been recruited only two weeks ago and signed up with other fellow villagers to maintain a local presence in that far western part of the country when the American troops leave.

He got his gun. He did his target practice. And he turned and killed two American special forces.

JEFFREY BROWN: Well, so the obvious question, that and many of these things, is to what extent these—who is carrying out these so-called insider attacks? To what extent is it infiltration from the Taliban? To what extent is it other things?

MARK THOMPSON: When you talk to folks at the Pentagon, they think it's 50/50.

Roughly 50 percent of these folks are infiltrators. They came in with that as their goal, sort of a human IED to explode down the road when the opportunity presented itself. But a lot of them, you know, are just personal grievances. There's a lot of friction between U.S. and allied forces and the Afghans.

Both come from very different backgrounds, and they don't always mesh well. So there is a mixture. And that is what makes it tough to stop.

JEFFREY BROWN: Taliban are taking credit, though, right?

MARK THOMPSON: Yes. Well, as Secretary of Defense Panetta said earlier this week, basically, they claim credit whenever any of these things happen.

And that's true. In fact, this past week, Mullah Omar the leader of the Taliban now in Pakistan, issued a statement taking credit for it. They have welcomed some of these guys who escaped back as heroes. So you can see the Taliban beginning to try to leverage these attacks to their own political ends.

JEFFREY BROWN: Well, one thing we do know is that they are happening more often, right? So, what is the Pentagon—they have said they're going to try to take some new steps.

MARK THOMPSON: Yes. Well, they have got an eight-step vetting process. They have had the eight-step vetting process for about six months.

It involves everything from drug checks, criminal checks, getting two letters from your local elders to vouch for you that you are a good guy, a good man, a good kid. But, plainly, the spate has increased dramatically—40 percent of the killings of this nature since 2007 have happened in the first seven months of this year.

So they're way up. And they're increasing counterintelligence. An order has gone out that U.S. and NATO troops should carry their weapons at all times, even when they are so-called inside the wire, on their base, not outside interacting with folks.

And there are now guardian angels. You know, if you have got three or four Americans training an Afghan platoon, one of them will simply stand and watch and be sure nothing is happening. So it's a very inefficient and demoralizing way to train a fighting force.

JEFFREY BROWN: I guess the other big question here is to what extent if any it is having an impact on the overall strategy of winding down and turning things over to the Afghans.

MARK THOMPSON: That's the problem, of course.

Number one, for the U.S. to leave and its allies to leave, they have got to train up the Afghan national security forces. They're really ramping that up. There are a lot more Afghans now being trained. And NATO will quickly point out that's one of the problems. We have got a lot more Afghans that we're interfacing with than was the case a year or two ago and that can account for some of the increase.

But plainly it does hamper the handoff, and that is a big concern in the military.

JEFFREY BROWN: All right, I want to turn to another vexing and actually very sad problem that you have been covering. That is the suicides in the military.

According to new figures from the military, in July, 26 active-duty soldiers in the Army took their own lives. That represented a big jump, more than twice the number reported for the month of June. The July figure was also the highest since the Army began reporting monthly suicides in 2009. And it made a total of 116 this year.

In the Marine Corps, there were eight suicides in July, up from six in June. The Marines have reported 32 so far this year, equaling the number for all of 2011.

So, Mark, you have been watching this over time, as have we on this program. What is the thinking about why the new spike?

MARK THOMPSON: Well, I think it's interesting.

We were just talking about these green-on-blue attacks. Suicides are the same way, in the sense that both are unexpected killings in a war zone. But the war has been going on for a decade, and that weighs heavily both on the guys fighting it on the American side, which can lead to suicide among really depressed soldiers, as well as these sort of green-on-blue attacks, as the enemy figures out the best way to—where we may be the most vulnerable.

Plainly, you talk to anybody in the military, yes, the turnstile deployments of U.S. troops has played a role. Many have not deployed. But there is an overall pressure on the U.S. military that has existed since 9/11.

And as we coast to the end of our presence in Afghanistan, as we already have done in Iraq, the military's mental health experts are saying something somewhat counterintuitive, that, you know, the soldier used to go for 12 months, come home, go, come home, go. They never really relax.

JEFFREY BROWN: And that was used to blame—I mean as a cause for a lot of this...

MARK THOMPSON: Right, but now you see when they are coming home and they're staying for a year or two or three, the family is trying to reintegrate in a way where it didn't try to reintegrate before.

So for the first time, the military, especially the Army, is seeing a spike in suicides among NCOs, non-commissioned officers. These are the older fellows who tend to be married—so, reintegration with the family is important—and have tried to make the Army a career, unlike a lot of the younger guys who come in for one or two tours and then are gone.

JEFFREY BROWN: We have got a chart I want to put up here that shows the increase.

And this is Army suicide. But this is interesting because as you are saying, it's going up and up and up, but even as the pace of deployments is going down, right, and after Iraq is over and as the drawdown in Afghanistan continues.

MARK THOMPSON: Yes, I mean, mental health problems in the military and elsewhere—you know, going to combat is like a seed.

It's planted. It doesn't sprout. It sprouts somewhere, you know, in the next rainy season, and whether that's six months or three years remains to be seen. But, generally, the impact of, you know, traumatic brain injury, of PTSD actually has to ripen. And it doesn't happen quickly.

JEFFREY BROWN: And of course the military has accepted this as a major problem. They talk about it a lot. They have implemented various programs. So what is the problem? I mean, are they not working or is this still an access problem, or are they not the solution?

MARK THOMPSON: No, there is an access problem and it remains a stigma problem, although those are going down.

But just like with the green-on-blue killings, Jeff, there are a lot of factors that play into both of these. Consequently, if you fix one, there are seven others. So there's no sort of one-size-fits-all solution. And that in part is why both are so vexing.

JEFFREY BROWN: All right, Mark Thompson of "TIME" magazine, thanks so much.

MARK THOMPSON: Thanks, Jeff.