Political leaders in Kirkuk Wednesday urged restraint and unity after the assassination of a top Sunni Arab politician in the northern Iraqi city sparked fears of a flare-up.

Mohammed Khalil al-Juburi, who headed the Arab bloc in the Kirkuk provincial council, was killed on Tuesday night when gunmen riddled his car with bullets.

The Islamic State jihadist group killed a senior Kurdish commander and five fighters Friday in a major attack in Iraq's Kirkuk province, while bombings elsewhere left at least nine dead.

The IS 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 Friday morning, a police brigadier general said.

Gunmen from the Islamic State jihadist group on Friday publicly executed two young men for allegedly cooperating with Iraqi security forces, officials and witnesses said.

The killings were carried out in the middle of the crowded main market in the Zab area of Kirkuk province.

Islamic State group fighters executed nine people on Friday in two northern Iraqi towns on suspicion of ties to anti-jihadist Sunni grassroots organizations, security sources and witnesses said.

In the town of Az-Zab, 90 kilometers (55 miles) west of the oil hub of Kirkuk, six people were executed in public.

Bombings in and near the Iraqi capital and a blast in the northern city of Kirkuk killed at least 22 people on Friday, security and medical officials said.

The attacks come as security forces and allied Shiite militiamen and Sunni tribesmen fight to regain ground from militants led by the Islamic State (IS) jihadist group who overran swathes of the country in June.

Islamic State jihadists kidnapped Thursday 20 people in a northern Iraqi village suspected of forming a local group to fight them, a security official and witnesses said.

The kidnappings were carried out in Kirkuk province by dozens of fighters from IS, which led a major offensive that overran large areas of Iraq in June.

Jihadists kidnapped dozens of residents of a northern Iraq village on Thursday after villagers burned one of their positions along with a jihadist flag, police and witnesses said.

The militants of the Islamic State (IS) group had withdrawn from Tal Ali in Kirkuk province on Wednesday, but returned in force on Thursday and abducted some 50 people, the sources said.

A series of blasts outside Shiite prayer halls killed four people and wounded 19 others on Friday in the northern Iraqi city of Kirkuk, police and medical sources said.

The deadliest blast took place in a car park outside the Mustafa prayer hall, or husseiniya, in the city's southwest, where a car bomb killed four worshipers and wounded 15 others after they had finished prayers.

The United Nations Security Council has denounced militant persecution of Christians and other minorities in Iraq, warning such actions can be considered crimes against humanity.

A suicide car bombing and a roadside bomb killed 13 people and wounded 21 others in the disputed northern city of Kirkuk on Friday, an Iraqi health official said.

Among the victims of the twin blasts at the city's southern entrance were four women, two children and two policemen, Sabah Mohammad Amin, the head of Kirkuk's health directorate, told Agence France Presse.