The explosion Sunday also wounded 19 others, Ramadi Mayor Abraham al-Owsag and 2 security officials told CNN. The terrorist was hiding among a group of new arrivals who had fled the city of Qaim, a city at the Iraq-Syria border and still under ISIS control, according to Owsag. He detonated his explosives as the group approached a security screening checkpoint at the entrance of a camp in the town of al-Wafa, 60 kilometers (37 miles) southwest of Ramadi, Owsag stated. ISIS claimed responsibility for the attack in a statement posted by the group's media wing, Amaq, saying it targeted members of the Iraqi military who were gathered at the camp's entrance. Mosul poised to fall The attack comes as Iraqi forces push ISIS elements out of their last major Iraqi stronghold, the northern city of mosul. Iraq's military has taken over the remains of the great mosque of al-Nuri, where Abu Bakr al-Baghdadi declared the ISIS "caliphate" in 2014, and is engaged in fierce street-to-street fighting for the last several hundred meters of Mosul's old town. "The fighting is heavy but our advance is strong," Brigadier Gen. Haider Fadl of Iraq's counterterror service told CNN Friday. "The difficulties are mainly due to the presence of civilians and the terrain. the houses are tight-knit and the streets are too narrow for our vehicles." ISIS militants are using small arms fire, snipers, mortars and grenades. at least four ISIS militants also blew themselves up close to the front line on Thursday, as well as one lady who blew herself up close to Iraqi forces on Thursday morning. The city is expected to be totally liberated imminently.