With an Iraqi government-led offensive underway to oust
More than 60 civilians were killed in attacks in Kirkuk, about 95 miles south of Mosul, and the death toll was expected to rise as security forces battled the militants in residential areas late into the night.
Also, a missile strike at a Shiite shrine outside the city late Friday killed at least 15 women and wounded about 50, according to Hassan Barham, an official with one of Kurdistan's main political parties, the Patriotic Union of Kurdistan.
Ali Husseini, a local spokesman for the Badr Shiite militia, said the attack struck a gathering of female mourners. Women could be heard shrieking in video uploaded by activists.
Ali Dalagi, an Iraqi army spokesman, said the strike came from a plane, and that the army was investigating.
U.S. coalition forces conducting Mosul offensive airstrikes released a statement saying they were investigating, but that it appeared they were not responsible.
"We cannot associate this with any coalition strikes in the area," the statement said, adding that the coalition, "adheres to targeting processes and procedures aimed to minimize risks to non-combatants."
Iraq's skies have become crowded in the last year as warplanes from a bevy of international and regional countries have conducted strikes against Islamic State.
In addition to those killed in the attack on the shrine, at least 63 people died and a hundred were wounded in clashes across the city, said Brigadier General Azad Jalal, assistant police chief in Kirkuk.
Jalal said it was unclear how many of those killed and wounded were police and security forces.
He said up to 70 militants staged the attack, and were stationed at the Al Snobar and Cihad Hotels and a mosque in the southern Domiz neighborhood. The Kurdish news agency Rudaw reported that 10 Islamic State snipers were on the loose in Domiz.
Jalal said some of the fighters came from outside the city.
"They were wearing ISIS clothes with long beards. They started their attacks with the help of some sleeper cells inside the city and we think those cells came with [displaced persons]," Jalal said. "Their goal was to distract us from Mosul offensive."
Islamic State claimed responsibility in a statement, saying its "knights of the caliphate" seized control of 10 neighborhoods, destroyed military vehicles, besieged the provincial government building, killed and injured people including an officer.
Militants also released photographs of themselves raising the Islamic State flag over a Kirkuk clinic.
Iraqi Prime Minister Haider al-Abadi, who is also general commander of Iraqi forces, has ordered additional troops to Kirkuk to assist in clearing the remaining ISIS militants from the city, the prime minister's media office has announced on its official Twitter account.
It has been almost two years since the last attack in Kirkuk, home to 10% of Iraq's oil reserves. Kirkuk is also a fulcrum for political and ethnic tensions, with the potential to make or break national reconciliation between Kurds, Arabs and Turkmen.
"It was expected that ISIS sleeper cells would make a move in Kirkuk one day," Kirkuk Gov. Najmaldin Karim told Rudaw. "Now that the Mosul offensive has started, they want to boost their own morale this way."
The Mosul offensive led by Iraqi troops began Monday with the help of Kurdish, tribal, militia forces and U.S. coalition airstrikes. Islamic State fighters seized the city of 1.2 million two years ago and have been fighting bitterly as Iraqi troops enter surrounding villages, attacking with mortar shells, snipers and suicide bombs.
Friday's attack in Kirkuk was multi-pronged: In the northwest, four militants armed with suicide vests stormed a power station and killed at least a dozen workers. At least one detonated his vest; all three died, officials said. Fighters also attacked hotels, police stations and other government buildings, according to reports and video posted by Rudaw.
Officials canceled Friday prayers and issued a curfew for the city of 900,000. Highways into the city were closed as Kurdish troops streamed in.
Kirkuk residents who claimed to be aiding security forces posted photographs online of uniformed, armed militants stalking their streets. Islamic State's Amaq news agency posted images of militants roaming after nightfall on foot, while others posted video of a truckload of fighters. Images broadcast on local television showed what appeared to be dead or injured fighters.
Late Friday, Islamic State snipers fought with security forces at three downtown hotels, taking hostages as human shields. But all were freed and security forces assumed control of the hotels, a peshmerga commander told Rudaw.
Aso Mamand, a member of the Patriotic Union of Kurdistan politburo, told Rudaw that the militants who stormed the city had been captured, killed or driven out. By 11 p.m., he said gunfire had ceased and the city was calm.
Analysts said the diversionary attack was one of several Islamic State staged across the country since the offensive started.
Patrick Martin, an analyst focused on Iraq at the Institute for the Study of War, a Washington-based think tank, said militants didn't attack Kirkuk oil facilities and that they were more likely trying to draw Kurdish forces back from the east side of Mosul.
Even if they ultimately lose Mosul, Martin said, Islamic State fighters, "can delay the operation, they can make it very slow and painful and lay the groundwork for their return."
Also Friday, he said, two Islamic State suicide bombers attacked a tribal leader about 170 miles south of Kirkuk outside Samarra. On Wednesday, Islamic State fighters launched suicide car bomb attacks against Kurdish troops west of Mosul. On Tuesday, they attacked tribal forces southeast of Kirkuk.
"ISIS remains a serious threat despite recent losses," he said, and the Kirkuk attack shows, "that ISIS's defensive measures extend across the whole country."
Islamic State released statements claiming to control portions of Kirkuk, but Kemal Kirkuki, a Kurdish peshmerga commander there, insisted the city, "is still under the control of the security forces."
"They use tactics to pose as [displaced persons] and attack from inside. We must be very careful and take it very seriously. We will not allow them to stay in Kurdistan," Kirkuki said of Islamic State.
Soldiers were on alert along the frontlines Friday.
Bartella, a Christian town about 20 miles east of Mosul, was recaptured from Islamic State Thursday, but Maj. Gen. Maan Al-Saadi, a commander with Iraq's Counter Terrorism Force, said forces remained wary of militants lurking a few miles west.
"They're trying to regroup there today and mount another attack," Saadi said as he stood at the edge of the city, where intense gunfire sounded and plumes of smoke loomed.
Hennessy-Fiske is a Times staff writer and Bulos is a special correspondent. Special correspondent Wael Resol in Irbil contributed to this report.
10:45 p.m.: Updated with Iraq's prime minister ordering more troops to Kirkuk.
2:00 p.m.: This article has been updated with additional details on attacks in Iraq and reaction.
1:00 p.m.: This article has been updated with information on a missile strike and additional comments from officials.
1:50 a.m. Oct. 21: Updated with the deaths of 11 power plant workers.