Gunmen opened fire at a Pakistan hospital where victims of an attack on Ahmadi mosques were being treated late Monday, sparking a shootout in which 12 people were killed, a doctor said.

The attackers opened fire at the gate of Jinnah Hospital in the city of Lahore, where victims and one of the alleged attackers in Friday’s suicide, gun and grenade attack on the minority sect were being treated, the doctor said.

“They started indiscriminate firing outside the emergency ward and intensive care unit,” Doctor Javed Akram told reporters.