KABUL, Afghanistan — Afghan army Sgt. Habibullah Hayar didn't know it, but he had been sleeping next to his enemy for weeks.
Twenty-four days ago, one of his roommates was arrested, suspected of plotting an insider attack against their unit, which is partnered with NATO forces in eastern Paktia province.
Afghan soldiers and policemen — or militants in their uniforms — have shot more than 50 foreign troops so far this year, eroding the trust between coalition forces and their Afghan partners.
An equal number of Afghan policemen and soldiers also died in these attacks, giving them reason as well to be suspicious of possible infiltrators within their ranks.
"It's not only foreigners. They are targeting Afghan security forces, too," said Sgt. Hayar, 21, who was in Kabul on leave. "Sometimes, I think what kind of situation is this that a Muslim cannot trust a Muslim — even a brother cannot trust a brother. It's so confused. Nobody knows what's going on."
The U.S.-led coalition said a NATO service member and an international civilian contractor were killed Saturday in the latest such insider attack.
The coalition said Sunday in a statement that Afghan soldiers also were killed or wounded, but provided no other details about the attack in eastern Afghanistan.
Insider attacks are taking a toll on the partnership, prompting the U.S. military to restrict operations with small Afghan units late last month.
The close contact — with coalition forces working side-by-side with Afghan troops as advisers, mentors and trainers — is a key part of the U.S. strategy for putting the Afghans in the lead as the U.S. and other nations prepare to pull out their last combat troops at the end of 2014, just 27 months away.
The U.S. military also has shown increasing anger over the attacks.
"I'm mad as hell about them, to be honest with you," Gen. John Allen, the top commander of U.S. and NATO forces in Afghanistan, told CBS' "60 Minutes" in an interview Sunday. "It reverberates everywhere across the United States. You know, we're willing to sacrifice a lot for this campaign, but we're not willing to be murdered for it."
So far this year, at least 52 foreign troops — about half of them Americans — have been killed in insider attacks.
The Afghan government has not provided statistics on the number of its forces killed in insider attacks.
But U.S. military statistics obtained by the Associated Press show at least 53 members of the Afghan security forces had been killed as of the end of August. A U.S. military official disclosed the numbers on the condition of anonymity because, he said, it was up to Afghan officials to formally release the figures.
An Afghan defense official who was shown the statistics said he had no reason to doubt their accuracy.
Overall, the statistics show that at least 135 Afghan policemen and soldiers have been killed in insider attacks since 2007. That's more than the 119 foreign service members — mostly Americans — killed in such attacks since then, according to NATO.
Typically, foreign troops are the main targets, but Afghan forces also have been killed by comrades angry over their collaboration with Westerners, and many more get killed in the crossfire, Defense Ministry spokesman Gen. Zahir Azimi said. He said the ministry did not have a breakdown of how many had been targeted or killed in gunbattles during the attacks.
In at least one instance, an Afghan police officer said to have ties to militants killed 10 of his fellow officers Aug. 11 at a checkpoint in southwestern Nimroz province.
An Afghan soldier also was killed April 25, when a fellow soldier opened fire on a U.S. service member and his translator in Kandahar province, the southern birthplace of the Taliban.
Last year, a suicide bomber in an Afghan police uniform blew himself up May 28 in Takhar province, killing two NATO service members and four Afghans, including a senior police commander.
And just a week before that, four Taliban fighters wearing suicide vests under police uniforms attacked a government building in Khost province, triggering a gunbattle that left three Afghan policemen and two Afghan soldiers dead.
On April 16, an Afghan soldier walked into a meeting of NATO trainers and Afghan troops in Laghman province and blew himself up, killing five U.S. troops, four Afghan soldiers and an interpreter.
"It's difficult to know an attacker from a non-attacker when everybody is wearing a uniform, Sgt. Hayar said.
The attacker was one of seven people rounded up last month from various units within the Afghan National Army Corps 203, Sgt. Hayar said. The corps covers the eastern Afghan provinces of Paktia, Paktika, Ghazni, Wardak, Logar and Khost.
"He was together with me in my room with some of my other colleagues. He had a long beard. We didn't know anything about him. We were living together, sleeping together," said Sgt. Hayar, who has been in the Afghan army for 2½ years.
He said the suspected infiltrator was identified after a Taliban militant arrested in Logar told his Afghan interrogators that members of the fundamentalist Islamic movement had infiltrated the corps and were planning imminent attacks. That prompted Sgt. Hayar's superiors to start questioning soldiers in various units.
Sgt. Hayar said his roommate's uneasy reaction raised suspicion, and investigators found Taliban songs saved to the memory card of his cellphone. He then was detained by Afghan intelligence officials and confessed he was a member of the Taliban and planned to stage attacks.
Sgt. Hayar says he assumes his former bunkmate was probably going after foreign forces, but it makes him uncomfortable nevertheless.
"It's very hard to trust anybody — even a roommate," he said. "Whenever I'm not on duty, I lock my weapon and keep the key myself. I don't put my weapon under my pillow to sleep because maybe someone will grab it and shoot me with my own weapon."