Twin bombings at a crowded market in Baghdad has killed at least 18 people and injured 44 more, police officials said.

Officials said the attack on Friday morning started with a bomb exploding near carts selling used clothes in the city's central Bab al-Sharqi area.

The second explosion went off two minutes later - apparently targeting people who rushed to help the victims from the first blast.

The bombings come as an attack near Kirkuk by the Islamic State of Iraq and the Levant group (ISIL) killed a senior Kurdish commander and five other fighters.

The ISIL assault on areas south and west of the northern city of Kirkuk began at around midnight, sparking fighting with medium and heavy weapons that was still ongoing on Friday morning, a police brigadier general said.

Brigadier General Shirko Rauf and five other members of the Kurdish Peshmerga forces were killed in clashes in Tel- Al Ward town, 35km south of Kirkuk, while 46 more were wounded, a police officer and a doctor told the AFP news agency.

Al Jazeera sources said that the Kurdish Peshmerga forces have since retaken a hill at Tel Al-Warid and parts of Maktab Khalid checkpoint that were previously under ISIL control.

Also on Friday, there was fighting within the city of Kirkuk, including a car bombing which caused an unknown number of casualties.

Sources told Al Jazeera that four ISIL snipers involved in the clashes within Kirkuk managed to gain access to a multi-storey building that used to be a hotel. All four were killed in clashes with Kurdish fighters that followed.

Al Jazeera's Jane Arraf, reporting from Baghdad, said that the fighting in Kirkuk had stopped, but clashes on the outskirts of the city continued.

"This was a bold attack by all accounts," she said. 

Iraq is facing its worst crisis since the 2011 withdrawal of US troops. Fighters from ISIL now control about a third of the country.

Source: Al Jazeera and agencies