At least 55 people have been killed on Saturday in attacks that targeted a Shi’ite Muslim gathering In Iraq,, a police check-point and the family of a Sunni paramilitary leader opposed to Islamic State.

The escalation comes as Iraqi forces are getting ready to launch an offensive to take back Mosul, the last Iraqi city still under control of Islamic State, in northern Iraq.

The heaviest toll was caused by a suicide bomber who detonated an explosive vest in the middle of a Shi’ite gathering in Baghdad, killing at least 41 people and wounding 33.

The explosion went off inside a tent filled with people taking part in Shi’ite Ashura rituals, which mourn the killing of Prophet Mohammad’s grandson Hussein in the 7th century. In an online statement Islamic State claimed the attack.