The ISIS terrorist group claimed responsibility on Wednesday for a drive-by shooting in a town north of the Iraqi capital Baghdad that left 8 people dead. The group, which usually exaggerates the number of casualties, put the figure at 22, describing them all as members of the Tribal Mobilization Forces. A security source had told Reuters that militants killed eight unarmed civilians in the assault in Tarmiya, 25 km (15 miles) north of Baghdad on Tuesday. The attack saw gunmen in two speeding cars open fire on civilians in Tarmiya. Iraq declared victory in December over ISIS, which had seized control of nearly a third of the country in 2014. But the group continues to carry out attacks and bombings in Baghdad and other parts of the country. Iraq is heading into parliamentary elections on May 12 — the first balloting since the government declared ISIS defeated in Iraq earlier this year. Among the casualties in Tarmiya were workers who were putting up election campaign posters for candidates running for parliament, police officials said. The officials and eyewitnesses spoke on condition of anonymity because they were not authorized to talk to the media. Last month, ISIS warned that anyone who runs for a seat or votes in the election will be considered an infidel, saying it will also attack polling stations. In an online video, it showed the shooting of what it described "two advocators" — meaning campaigners — for the vote in Tarmiya. A few days later, the militant group released an audio message accusing Iraqs government of being an agent for Iran. Nearly 7,000 candidates will vie for 329 seats in the May 12 parliament elections, the fourth since the 2003 U.S.-led invasion. Some political parties have expressed concerns that the unstable security situation in some parts of northern and western Iraq, as well as the fact that some 2.3 million people are still uprooted from their homes following the three-year military campaign against ISIS would affect the turnout in those areas. Despite its defeat, US and Iraqi officials have said that ISIS is likely to continue launching insurgent-style attacks. In January, ISIS carried out back-to-back suicide bombings in central Baghdad, killing at least 38 people, and a month later, it ambushed a group of Iraqs Popular Mobilization Forces near Kirkuk, killing at least 27.