At least 11 people were killed and 21 others wounded after a state-run cooking gas factory was attacked in Taji in the northern outskirts of Baghdad, Iraq, on Sunday, according to police officials. The Islamic State has claimed responsibility for the incident, authorities told CNN.

A suicide car bomb exploded at the factory’s entrance at around 6 am local time. Soon after, six militants wearing explosive vests entered the facility and clashes with security forces ensued, Reuters reported. A second suicide bomber reportedly set off a bomb in the factory premises, CNN reported.

Three of the factory’s gas storage units were set on fire in the attack, a spokesman for the Baghdad Operations Command said. The casualties included policemen.