At least 12 people were killed after a suicide bomber blew himself up inside a Shiite mosque in Baghdad. The attack is a continuation of a Sunni insurgency led by the Islamic State group that has stepped up its offensive on the Iraqi capital.

The suicide bomber was wearing a vest with explosives as worshippers were leaving a mosque in eastern Baghdad, a police officer told the Associated Press. About 26 people were injured in the attack in the New Baghdad section of the Iraqi capital.

There has been a spike in attacks targeting Baghdad since the Islamic State, the Sunni militant group formerly known as the Islamic State of Iraq and Syria, or ISIS, declared a caliphate in June from territory it seized in Iraq and Syria.