Marine Gen. Joseph Dunford, the commander of U.S. and allied forces in Afghanistan, offered his “personal apology and condolences to the family of the boys who were killed” and said the coalition takes full responsibility for the deaths.

A statement issued by the coalition says the boys were killed Thursday when coalition forces fired at what they thought were insurgent forces in the Shahid-e Hasas district of Uruzgan province. It says a joint Afghan-NATO investigation team visited the location Saturday and met with local leaders.

The killing of civilians by foreign forces has been a major source of tension with the Afghan government throughout the nearly 12-year-old war.

According to a recent report by the United Nations, 2,754 Afghan civilians were killed last year, down 12 percent from 3,131 in 2011. But the number killed in the second half of last year rose, suggesting that Afghanistan is likely to face continued violence as the Taliban and other militants fight for control following the impending withdrawal of U.S. and allied combat forces.

The U.N. said the Taliban and other insurgents were responsible for 81 percent of the civilian deathsand injuries last year while 8 percent were attributed to pro-government forces. The remaining civilian deaths and injuries could not be attributed to either side.

The number of casualties blamed on U.S. and allied forces decreased by 46 percent, with 316 killed and 271 wounded last year. Most were killed in U.S. and NATO airstrikes, although that number, too, dropped by nearly half last year to 126, including 51 children.

KANDAHAR: A police truck packed with officers and detainees struck a roadside bomb in southern Afghanistan’s largest city, killing 10 of those aboard, officials said Sunday.

It was one of four blasts Saturday that left at least 24 people dead across the country. Attacks by insurgents are a daily occurrence around Afghanistan and the Afghan police with their unarmored pickup trucks and remote checkpoints are a common target.

In the Kandahar city blast, police had driven out into a residential neighborhood of the city at night to inspect a bomb that had been found there, said Javid Faisal, a spokesman for the provincial government. They detained three suspects and were driving back with them in a police pickup truck when the vehicle struck another explosive buried in the road. Eight police officers and two detainees were killed in the blast.

Meanwhile, Afghan authorities accused NATO of killing three civilian men in a nighttime ambush in the eastern Logar province. The coalition disputed the account, saying it had no operations in Logar’s Baraki Barak district Saturday night. NATO said there were three dead, but they were insurgents killed by Afghan forces.

Deputy provincial police chief Rais Khan Abdul Rahimzai said all three of the added were civilians. “They were brothers. They had dinner at one of their brother’s houses in another part of the district and it was when they were driving back that they were ambushed by the foreign soldiers,” Rahimzai said. “It was a misunderstanding in which foreign forces shot and killed three people.”

A spokesman for the international force disputed the Afghan version of the incident.”This was the ANSF,” said Maj. Martyn Crighton, referring to the Afghan National Security Forces. He said they went after three men who had been seen burying a bomb in the ground and “got engaged in a firefight with these guys.”

It was not possible to reconcile the conflicting accounts.

Earlier Saturday, 10 policemen were killed when a suicide bomber on a motorcycle blew himself up in Kunduz province in the north. Meanwhile, a remote-controlled bomb planted on a bicycle exploded in the eastern city of Ghazni, killing one police officer and a civilian. And officials in Farah province in the west said Sunday that two police officers were killed there Saturday evening when their vehicle hit a roadside bomb.