COMBAT OUTPOST SABARI, KHOST PROVINCE, AFGHANISTAN — An Afghan soldier had spotted the tiny wire in the road, bringing the convoy of Humvees to a halt.

Soldiers trailed the wire to a 30-pound explosive device, where a second bomb had been rigged to blow up whoever came to help the victims of the first. That’s when they saw the young man running across the field off the road.

After he was caught and identified as an insurgent by a fingerprint check and retinal scan, the Afghan soldiers beat him, first with rifles and then with switches, as the Americans looked on disapprovingly.

“It’s their fight now,” said Lt. Alex Graves, leader of the platoon that was patrolling with the Afghans.

Graves did not witness the beating of the suspect, but he sees the differences in the Afghan way of doing things.

“They’re never gonna do it to the American standard, but to an Afghan standard,” he said.

The U.S-led coalition of military forces has spent years training the Afghan soldiers and police in professional conduct so they earn the respect and full support of the Afghan people. But some here worry that the Afghans, who in June took over security from the coalition, may drop some of those standards once the coalition removes most of its combat troops in 2014.

That could alienate the public and give the Taliban the opening back into the hearts of the people that they’ve been denied for the 11 years that the Americans have been here fighting.

“There is a lot of discipline and training with the Afghan National Army, but, of course, the starting level is so low that I am not sure the majority of the soldiers understand the rights of a prisoner,” said Yama Torabi, executive director of Integrity Watch Afghanistan.

KABUL — Of all the challenges the United States faces as it winds down the Afghanistan war, the most difficult might be closing the prison nicknamed “The Second Guantanamo.”

The United States holds 67 non-Afghan prisoners there, including some described as hardened al-Qaida operatives seized from around the world in the months after the Sept. 11, 2001, attacks. More than a decade later, they’re still kept in the shadowy facility at Bagram air base outside Kabul.

Closing the facility presents many of the same problems the Obama administration has encountered in its attempt to close down the Guantanamo Bay detention center in Cuba. Some U.S. officials argue that Bagram’s resolution is even more complicated — and more urgent. The U.S. government transferred the prison’s Afghan inmates to local authorities this year. But figuring out what to do with the foreign prisoners is proving to be an even bigger hurdle to shutting the American jail.

“Is there a plan? No. Is there a desire to close the facility? Yes,” Gen. Joseph F. Dunford Jr., the top U.S. general in Afghanistan, said in an interview.

With the United States’ nearly 12-year fight in Afghanistan due to end next year, the State Department and the Pentagon have been unable to come up with a strategy for the trial or repatriation of men from more than a dozen countries held at Bagram. Meanwhile, the population in the prison is growing because of the apprehension of foreign fighters in joint U.S.-Afghan Special Forces operations. The newest detainee was sent to Bagram last month.

None of the prisoners have been formally tried. Many have been cleared for release by informal military review boards, but most of those were never freed.

Because the detention center is on Afghan soil, U.S. forces are technically obliged to shutter it when their combat role here formally ends in December 2014. But some U.S. officials and politicians say that would pose an enormous security risk.

The best solution, they say, is to keep the facility open under U.S. oversight, possibly for decades. It is not at all clear, though, that the Afghans will permit that.