Four hostages -- employees of the Iraqi North Oil Company -- were taken captive after four attackers, believed to be wearing suicide vests, stormed the Bai Hassan oil field northwest of Kirkuk on Sunday, the source said.
One of the attackers blew himself up when security forces responded. The other attackers were later killed by security forces.
The ISIS-affiliated Amaq news agency released a statement claiming responsibility for the attack, which was widely circulated by the terror group's supporters on social media networks.