Three Americans are dead after an Afghan officer open fired at a hospital in Kabul on Thursday.

The gunman, a police officer, killed one doctor and two medical staff in the attack that occurred at around 9 a.m. at the CURE facility, one of many American-run, Christian hospitals around the world, The Washington Post reported. Several others were also wounded.

The shooter tried to turn the gun on himself, but was unsuccessful, Afghan Interior Ministry spokesman Sediq Seddiqi told the newspaper. The suspect is now in custody.

"With great sadness we confirm that three Americans were killed in the attack on CURE Hospital," the U.S. Embassy in Kabul said in a statement obtained by the newspaper. "No other information will be released at this time."

The identities of the victims have not been released. An Afghan Health Ministry spokesman confirmed that one was a doctor employed by the hospital and the two others were visiting staffers- a father and son, Reuters reported.

"As they were walking out of the hospital, the security guard opened fire on them, killing three and wounding another one," an Interior Ministry official told Reuters.

The hospital, run by a Pennsylvania-based charity, provides medical treatment for underprivileged children, according to The Washington Post. The attack comes at a time of escalating violence against foreigners in Afghanistan. Many attacks were carried out in the capital by the Taliban in protest of the country's recent presidential elections. But others have been carried out by Afghan officials.

Associated Press photographer Anja Niedringhaus was killed at the beginning of April after a police officer open fired inside her car that was traveling in a convoy delivering election ballots in eastern Afghanistan. A Taliban attack in March killed nine people, including two Canadians, at a hotel in Kabul, The Washington Post reported.  

"They were not the people carrying guns, they did not have military uniforms, they came here under immense pressure and were here only to serve the people of Afghanistan," Health Minister Suriya Dalil told Reuters of Thursday's attack. "This was an inhumane and brutal action, and unfortunately will impact our health services."