ISIL fighters have attacked multiple targets in and around the oil-rich city of Kirkuk, in a major assault that appeared aimed at diverting Iraqi and Kurdish forces from a massive push against Mosul, the armed group's last major stronghold in Iraq.
The coordinated attacks began early on Friday when fighters armed with assault rifles and explosives attacked a power station and government buildings, including the police headquarters.
ISIL, also known as the Islamic State of Iraq and the Levant, or ISIL, quickly claimed responsibility for the attacks in online statements.
In one of the incidents, at least three suicide bombers were killed as security forces foiled an attack on a former police complex in central Kirkuk.
Kirkuk Governor Najmaldin Karim said ISIL members split up into groups of three to five fighters and spread out to five areas in the city after infiltrating on foot.
"We have been able to neutralise four of those places. There is only one place with one person left in it - the others were killed - and hopefully that will be taken care of in the next hour or two," Karim told Al Jazeera over the phone.
"They came to die. They came to inflict as much damage as they can and either blow themselves up or die in the firefight ... They are facing defeat on so many fronts that they resort to these kind of actions."
Outside Kirkuk, at least 10 employees at a power plant, including three Iranian nationals, were killed when gunmen stormed the facility and then blew themselves up, according to authorities.
READ MORE: Attacks target energy facilities in Kirkuk
Al Jazeera's Hoda Abdel-Hamid, reporting from outside the city, said intense exchanges of gunfire took place in several districts of Kirkuk.
"It is a very volatile situation," Abdel-Hamid said. "The residents of Kirkuk have been told to remain indoors until further notice."
A police colonel said at least six policemen and 12 ISIL fighters had been killed in the clashes, mostly in southern neighbourhoods, a toll confirmed by other officers, according to AFP news agency.
Kemal Kerkuki, a senior commander of Kurdish Peshmerga forces west of Kirkuk, said the town where his base is located also came under attack on Friday. He said the base is now under control.
According to Kerkuki, ISIL maintains sleeper cells in Kirkuk and the surrounding villages.
"We arrested one recently and he confessed," he told the Associated Press news agency, adding the attackers may have posed as displaced civilians in order to infiltrate the city.
READ MORE: Mosul battle could cause a 'human catastrophe'
Witnesses also reported gunfire and explosions, while live footage from the Kurdish Rudaw TV showed smoke rising from the city, where a curfew has been declared.
The wave of attacks comes as the Iraqi government and Kurdish forces are making a major push to drive ISIL from Mosul, Iraq's second-largest city.
Iraqi officials said they had advanced as far as the town of Bartella, 15km from Mosul's outskirts, by Thursday.
ISIL, which still controls a swath of territory stretching across Syria and Iraq, has a history of launching diversionary attacks on distant fronts when it comes under pressure.
Kirkuk, an oil-rich city some 290km north of Baghdad and 170km southeast of Mosul, is claimed by both Iraq's central government and the country's Kurdish region.
…. They are facing defeat on so many fronts that they resort to these kind of actions."
Source: Al Jazeera News And News Agencies