At least three American doctors have been killed by a security guard at an international hospital in the Afghan capital, Kabul, Afghan security sources say.
Hafiz Khan, district police chief, said the guard suddenly started shooting on Thursday morning in Cure Hospital in the west of the capital, according to AP news agency.
Khan says the attacker was a member of the Afghan Police Protection Force assigned to guard the hospital, which specialises in children's medicine.
"Five doctors had entered the compound of the hospital and were walking toward the building when the guard opened fire on them", said Bektash Torkystani, a Ministry of Health spokesman.
"Three foreign doctors were killed and two other doctors were wounded."
With great sadness we confirm that three Americans were killed in the attack on CURE Hospital
Another policeman in the area shot the attacker, injuring him.
The attacker was in surgery at midday in the same medical facility under heavy police guard.
Attacks targeting foreigners
The US embassy said the three doctors killed were US citizens. "With great sadness we confirm that three Americans were killed in the attack on CURE Hospital," the US embassy said on its Twitter account. "No other
information will be released at this time."
Cure International is a non-profit organisation founded in 1998, based in Pennsylvania and working in 29 countries including Afghanistan.
It describes itself as an "unapologetically Christian organisation" on its website, adding that it offers "treatment regardless of gender, religion, ethnicity, or ability to pay".
Its hospitals and health programmes specialise in treating children with conditions including clubfoot, cleft lips, burn injuries and brain diseases.
Cure International took over the hospital in west Kabul in 2005 at the invitation of the Afghan government, and runs obstetrics, gynaecology, pathology and surgery departments as well as training schemes for doctors and nurses.
There was no immediate comment from Taliban spokesmen after the hospital shooting.
The shooting is the latest attack on foreign civilians in Afghanistan after the bombing of a popular restaurant in January and an attack on an upscale hotel in March.
It also follows the shooting of two Associated Press staff by a police officer in the country's east this month.