KABUL — An American general was killed Tuesday after a shooter wearing an Afghan military uniform opened fire at a training facility in Kabul, U.S. officials said.

The killing is “one of the highest-ranking deaths in the war since 9/11,” Pentagon spokesman Rear Adm. John Kirby told reporters.

The gunman, who was killed, was believed to be an Afghan soldier who had served for some time, according to a Pentagon official.At least 15 coalition troops, including other Americans, were wounded in the attack, U.S. officials said.

The incident happened at Marshal Fahim National Defense University in Kabul, said NATO’s International Security Assistance Force in a statement, clarifying earlier information from ISAF which reported that the shooting happened at Camp Qargha.

The German military said that the violence broke out during a “key leader” event. It also said that one person was killed and 14 were injured, including a German brigadier general.

The Afghan Defense Ministry described the shooter as a “terrorist” and said Afghan soldiers shot him dead.

In the past, people dressed as Afghan security forces have attacked coalition forces who have worked to thwart such violence.

In 2012, so-called “green on blue” attacks took the lives of dozens of coalition troops, and the U.S. command in Kabul halted some joint operations with Afghan security forces.

Two attackers wearing Afghan military uniforms killed two U.S. service members in February in Afghanistan, military publication Stars and Stripes reported.In October 2013, a man in an Afghan soldier’s uniform shot and killed a member of ISAF in eastern Afghanistan.