An Afghan security guard has opened fire at a hospital in Kabul, killing three American doctors, in the latest attack on foreigners in Afghanistan.
Thursday's attack took place at a hospital run by the U.S.-based Christian charity CURE International. In a brief statement on Twitter, the U.S. Embassy said with "great sadness, we can confirm that three Americans were killed in the attack on CURE hospital."
Afghan officials said a fourth American was wounded in the shooting and that two of the dead were father and son physicians who were visiting the hospital at the time of the attack. The third doctor killed had worked at the Kabul facility for seven years.
In a post on its website, CURE said the shooter was not an employee of CURE but a member of the security detail assigned to the hospital. The charity said the assailant "shot himself after the attack" and was initially treated at the CURE hospital before being transferred into the custody of the Afghan government.
Afghan Interior Ministry spokesman Sadiq Sidiqqi said an investigation is under way.
"This was an unfortunate incident this morning. The attacker was a police security guard there and he opens fire on foreign nationals who went there and unfortunately three of them have been killed. One is injured and the injured has been taken to the hospital. And the police has arrested the attacker as well so we will investigate to find out the motives behind this attack."
It is unclear whether the Taliban is responsible for the shooting.
CURE's website says the organization began operating the International Hospital in Kabul in 2005. CURE says the hospital is focused on maternity and pediatric care and serves 37,000 patients a year.
NATO on Thursday strongly condemned the "heinous" attack, calling it an "appalling crime against civilians who worked to make Afghanistan a better place and to help the sick and injured."
A NATO official added that the process of handing over security to Afghan forces is on track and will be completed at the end of the year. The official said, "we expect there will still be fighting and there will still be an insurgency in 2015, but what matters is that the Taliban do not represent an existential threat to the functioning of the Afghan state."
Foreign civilians in Afghanistan have been the target of a rising number of attacks this year.
Earlier this month, a police officer shot two Associated Press journalists in the eastern part of the country.
In March, a Swedish journalist was killed outside a Kabul restaurant.
Twenty one people were killed in January in a bombing at a Lebanese restaurant in Kabul's diplomatic district.