A group of gunmen stormed a cafe in a town north of the Iraqi capital on May 13, leaving at least 13 people dead and 15 wounded.
The attack occurred in Balad, a predominately Shi'ite town about 80 kilometers north of Baghdad.
The Islamic State (IS) extremist group posted a statement online claiming responsibility for the attack.
The assault in Balad comes just days after the deadliest violence in Baghdad this year killed 93 people and wounded 165 in a wave of bombings that was claimed by the Islamic State (IS) extremist group.
Three gunmen, armed with machine guns, opened fire into the crowd in the cafe in Balad early on May 13.
Once police arrived at the scene, two of the attackers detonated their suicide vests.
Similar attacks in the past have been blamed on the IS extremist group, which still controls vast areas of northern and western Iraq and has frequently targeted the country's Shi'a majority, which it considers heretics.