KABUL, AFGHANISTAN: A British helicopter crashed in southern Afghanistan on Saturday, killing five NATO troops in the single deadliest day this year for foreign forces as they prepare to withdraw from the country, officials said.

The British defense ministry confirmed that all five of the dead were British. ?Maj. Gen. Richard Felton, commander of the Joint Helicopter Command, said the crash appeared to be “a tragic accident.”

In Kabul, meanwhile, an Afghan university official identified two Americans killed by a local policeman at a hospital in the capital earlier this week.

The shooting of health clinic administrator John Gabel and his visiting father, Gary Gabel, was the latest by a member of Afghanistan’s security forces against those they are supposed to protect. Also killed in the attack was pediatrician Dr. Jerry Umanos, who had been identified soon after the attack. John Gabel’s wife also was wounded in the attack. All four were from the Chicago area.

The cause of Saturday’s helicopter crash was not immediately known. Kandahar provincial police spokesman Zia Durrani said the aircraft went down in the province’s Takhta Pul district in the southeast, about 31 miles from the Pakistani border.

The coalition said it was investigating the circumstances of the crash but said it had no reports of enemy activity in the area.

Saturday’s crash was one of the deadliest air accidents involving Britain’s forces in Afghanistan. In September 2006, a Nimrod surveillance aircraft exploded in mid-air while supporting NATO ground operations near Kandahar, killing all 14 servicemen on board.

A Taliban spokesman claimed in a text message Saturday that the insurgents shot down the helicopter.

“Today, the mujahedeen hit the foreign forces’ helicopter with a rocket, and 12 soldiers on board were killed,” spokesman Qari Yousef Ahmadi said. The insurgents frequently exaggerate death tolls in their attacks and falsely have claimed responsibility for incidents before.

The last deadliest day for coalition forces was Dec. 17, 2013, when a helicopter crash killed six U.S. service members.

Saturday’s deaths bring to seven the number of international troops killed this month. So far this year, 23 have been killed, according to an Associated Press count, a far lower number than previous years as international troops have pulled back.