Iraq has launched a large-scale military operation to regain control of the city of Falluja, held by anti-government fighters since December, the Defense Ministry said Friday.

Soldiers and police officers have killed many fighters from the Islamic State of Iraq and Syria and confiscated a large amount of weapons and several vehicles. On Friday, military shelling left 13 dead and 27 others wounded, health officials said. Mosques and houses were damaged.

About 700,000 people live in Falluja, a Sunni city in Anbar province west of Baghdad. More than 300 people, most of whom are civilians, have been killed in Falluja since the beginning of the year.