KABUL, Afghanistan (AP) -- The U.S. Embassy in Afghanistan says three doctors killed by an Afghan security guard at a Kabul hospital are American citizens.
Thursday's shooting at Cure International Hospital in western Kabul was the latest attack on foreign civilians in the Afghan capital this year.
The embassy says on Twitter: "With great sadness we confirm that three Americans were killed in the attack on Cure hospital."
The motive for the attack was unclear.
THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.
An Afghan security guard opened fire on a group of doctors at a Kabul charity hospital on Thursday morning, killing three foreign physicians and wounding two other people, officials said.
The shooting at Cure International Hospital in western Kabul was the latest attack on foreign civilians in the Afghan capital this year. The nationalities of the three killed doctors were not immediately known.
The attacker was a member of the Afghan Police Protection Force assigned to guard the hospital, according to District Police Chief Hafiz Khan. He said the man's motive was not yet clear.
The attacker was wounded and in custody. He was in surgery at midday in the same medical facility under heavy police guard, according to Kanishka Bektash Torkystani, a Ministry of Health spokesman.
"Five doctors had entered the compound of the hospital and were walking toward the building when the guard opened fire on them," Torkystani said. "Three foreign doctors were killed and two other doctors were wounded."
It was also unclear how the attacker was wounded.
According to its website, the Cure International Hospital was founded in 2005 by invitation of the Afghan Ministry of Health. It sees 37,000 patients a year, specializing in child and maternity health as well as general surgery. It is affiliated with the Christian charity Cure International, which operates in 29 countries with the motto "curing the sick and proclaiming the kingdom of God."
The Afghan capital has seen a spate of attacks on foreign civilians in 2014, a worrying new trend as the U.S.-led military coalition prepares to withdraw most troops by the end of the year.
It was unclear whether the Taliban were behind Thursday's shooting, though the insurgents have claimed several major attacks that killed foreign civilians this year, an escalation after years of mostly targeting foreign military personnel and Afghan security forces.
In January, a Taliban attack on a popular Kabul restaurant with suicide bombers and gunmen killed more than a dozen people, while in March gunmen slipped past security at an upscale hotel in the Afghan capital and killed several diners in its restaurant.
The hospital shooting is also the second "insider attack" by a member of Afghan security forces targeting foreign civilians this month.
On April 4, an Afghan police officer shot two Associated Press staff working in the eastern province of Khost, killing photographer Anja Niedringhaus and wounding veteran correspondent Kathy Gannon.