Angry young men stormed an Ebola treatment hospital in eastern Congo on Sunday evening, sparking panic as medical staff scrambled to evacuate patients amid gunfire in the area.

It was not immediately clear whether anyone was injured in the attack on Mongbwalu General Hospital. The hospital’s medical director, Dr. Richard Lokudu, told The Associated Press (AP) that the assailants demanded the release of two bodies of relatives.

“There was gunfire and the medics were trying to evacuate the patients and the staff,” Lokudu said by phone, adding that the facility had been placed on high alert but providing no further details as events unfolded.

The incident marks the third attack in a week on health care facilities struggling with limited resources amid an Ebola outbreak.

The World Health Organization (WHO) has declared the situation a public health emergency of international concern, underscoring the strain on an already fragile response system.