BAGHDAD (Reuters) - Islamic State has claimed a suicide bombing that killed at least 15 people and injured 16 at a wedding party near the holy Shi’ite city of Kerbala late on Sunday.

Five assailants including the suicide bomber attacked the celebration in Ain al-Tamr, west of Kerbala in southern Iraq, firing machine guns and throwing hand grenades, the police said. All the attackers were killed by security forces.

The bombing is the first in the Kerbala region since Iraqi forces dislodged Islamic State militants from their stronghold in Falluja, 80 km (50 miles) north of city.

The ultra-hardline Sunni group has been retreating since last year in the face of government forces backed by a U.S.-led coalition and Iranian-supported Shi’ite militias.

But it remains in control of parts of northern and western Iraq and continues to claim bombings all over the country, targeting mainly Shi’ite districts and cities.

A statement on the Amaq news agency that supports Islamic State said the attack was carried out by four of its suicide fighters against a “gathering of Shi’ites”.

Initial reports in local media late, citing security sources, blamed the killings on a dispute between two tribes at the wedding party.

Islamic State claimed a truck bomb that killed at least 325 people in Baghdad’s Karrada shopping street in July, the deadliest attack since the U.S.-led invasion that toppled Saddam Hussein in 2003.