Iraqi officials say police have unearthed two mass graves in the western city of Ramadi, with bodies of about 40 people killed by Islamic State militants.

The officials say the people were killed when the extremist Sunni group ruled the city. They say arrested IS militants led authorities on Tuesday to the site of the mass graves, inside the city's soccer stadium.

The two officials say bodies of women and children were among those found, along with bodies of men in civilian clothes. The officials spoke on condition of anonymity as they were not authorized to talk to reporters.

Ramadi, the provincial capital of Anbar, fell to IS in May, a major setback for U.S.-allied Iraqi forces at the time. It was liberated in December.