An affiliate of the Islamic State group claimed responsibility overnight for a deadly suicide bombing inside a Shiite mosque on the outskirts of Pakistan’s capital that killed 36 people and wounded 169 others, as mourners gathered Saturday under tight security at the same mosque for funerals for the victims.

The regional Islamic State affiliate, known as Islamic State in Pakistan, claimed responsibility in a statement posted on its Amaq News Agency. It said the attacker opened fire on security guards who tried to stop him at the main gate and detonated his explosive vest after reaching the mosque’s inner gate.