UPDATED: 4 civilians killed in suicide bombing at Baghdad-Kirkuk road

Diyala (IraqiNews.com) Four civilians were killed and nine others were wounded Thursday when attackers, presumably from the Islamic State, boarding booby-trapped cars, targeted checkpoints on the Kirkuk-Baghdad road in Diyala, an official has said.

Udai al-Khadran, mayor of al-Khales town, was quoted saying that an attack by trapped vehicles left 13 casualties, adding that some of those wounded were in a critical condition.

Alghad Press website had quoted security sources earlier saying that three booby-trapped cars exploded at the Ascia Cell and Madra security checkpoint in al-Khales region. It said that one of the vehicles was detonated by the security forces after arresting its driver. The attack wounded two soldiers prompted security forces to close the road, according to the website.

Since Iraqi forces launched a campaign in October to retake the city of Mosul from Islamic State militants, the extremist group stepped up attacks at other provinces, targeting civilians and security personnel. Observers say the group might be trying to divert security attention from Mosul or to cover up its losses there. It has, however, reportedly sustained severe losses in personnel and finances, with many of its leaders either killed or fled to neighboring Syria, where the group is also struggling to defend its foothold.

Besides Mosul, IS is still maintaining smaller pockets in Anbar, Salahuddin and Kirkuk. Iraqi and U.S.-led coalition fighter jets occasionally carry out airstrikes targeting those locations, but no official orders have yet been given for a ground invasion of those regions, apparently as the government is giving full attention to the Mosul campaign.