Militants have attacked a gas facility and an oilfield in northern Iraq, killing five people.

Gunmen on motorbikes opened fire on the facility’s guards, then killed four of its employees and planted bombs before escaping, officials from Iraq’s North Oil Company and Kurdish peshmerga forces said on Sunday.

Militants also attacked the nearby Bai Hassan oilfield, the largest in oil-rich Kirkuk province, killing an engineer and causing a major fire, officials said. Attacks inside Kurdish-controlled areas of the province are rare.

A peshmerga colonel said security forces had killed two suicide bombers at the oilfield. A third detonated explosives, setting oil tanks ablaze, and a fourth was still at large.

Brig Gen Sarhad Qader confirmed that three bombers were dead. An engineer was also killed in the assault and seven people were wounded, according to the peshmerga colonel.

The jihadi-linked Amaq agency, which often carries claims of Islamic State attacks, said the assault on Bai Hassan had taken place, but did not attribute it to Isis.

There was no immediate claim of responsibility for the attack on the gas facility. It may have been carried out by Isis, but it is more common for the group’s militants to fight to the death in such assaults.

Forces from Iraq’s autonomous Kurdistan region control part of Kirkuk and Isis also holds territory in the province.

The group overran large areas north and west of Baghdad in 2014, sweeping Iraqi security forces aside, but it has since lost significant ground.

After federal forces retreated, Kurdish troops gained or solidified control over a swath of northern territory claimed by Baghdad and Kurdistan.

Iraqi forces and Kurdish troops are battling the jihadis, but they have fought largely independent wars so far.

That will have to change during the battle for Mosul, Iraq’s second city, because the operation is expected to require federal and Kurdish forces.