A US Air Force F-16 fighter jet crashed near an American military base in western Germany on Tuesday, with the pilot ejecting before impact.

The F-16 Fighting Falcon, assigned to the 52nd Fighter Wing, went down near Spangdahlem Air Base in the state of Rhineland-Palatinate at around 2:30pm local time, the US military said. The pilot was taken for medical treatment.

According to Germany’s air traffic control authority, four F-16s had been taking part in a training exercise. Two remained in the training area while the other two returned toward Spangdahlem, with one believed to have crashed while approaching the base. The remaining aircraft subsequently landed at Ramstein Air Base.

Videos from the area showed a large plume of dark smoke rising near the base as emergency crews responded to the crash.

The cause of the crash remains under investigation, the US military said.

Spangdahlem hosts the US Air Force’s 52nd Fighter Wing and is one of Washington’s key military installations in Germany. The wing operates F-16s and supports US and NATO missions in Europe and elsewhere. Around 5,000 US military personnel and family members are based at the installation, according to AP.

Spangdahlem’s F-16s have also been involved in the US military buildup around Iran. Aircraft from the base’s 480th Fighter Squadron were deployed to the Middle East in July as Washington resumed strikes against Iranian targets following the collapse of a temporary ceasefire.