According to security officials, heavy clashes broke out on Wednesday in three areas outside the city of Tikrit. Twelve members of security forces, Shia fighters as well as civilians were killed in the skirmishes and 37 others sustained injuries.
ISIS attacked the Iraqi security forces with three car bombs during the fighting.
In a separate development, mortar shells hit two neighborhoods in the capital, Baghdad, claiming at least 10 lives, officials said.
In one of the attacks that targeted a commercial area in the northern Shula neighborhood, seven civilians, including two women, died, while shortly afterward Sabi al-Bore neighborhood also came under attack in which three civilians lost their lives.
ISIS currently controls parts of both Iraq and Syria. The terrorists seized Tikrit, which is located about 130 kilometers (80 miles) north of Baghdad, in summer 2014.
The terrorists posted a message on Twitter Wednesday claiming responsibility for blowing up three explosives-laden trucks in coordinated attacks on Iraqi troops and Shia fighters.
The attacks were carried out near Camp Speicher, 160 kilometers (100 miles) north of Baghdad, in Salahuddin Province.
The assailants driving the vehicles were named as Abul Talha al-Firansi, a Frenchman; Abu Omar al-Qatari, from Qatar and Abu Ukasha al-Shami, from Syria.
Camp Speicher, situated outside Tikrit, witnessed a brutal mass killing in June 2014, when nearly 1,700 soldiers were slaughtered by the ISIS terrorists.
Based on estimates by the US government, the ISIS has about 20,000 members, with around 3,400 believed to be foreigners.
