BAQUBA, Iraq (Reuters) - Three Shi’ite Muslim pilgrims were killed by a roadside bomb as they walked to a holy site near the northeastern Iraqi city of Khanaqin on Tuesday, police said.

Islamic State claimed responsibility for the attack, the group’s news agency Amaq reported.

The claim could not immediately be verified. The Sunni Muslim militants are active in the area and have targeted Shi’ite pilgrims in the past.

Hundreds of thousands of Shi’ite Muslims gather every year in Iraq for the annual pilgrimage of Arbaeen, which marks the end of a 40-day mourning period for the grandson of the Prophet Mohammad, Imam Hussein.

Islamic State has waged a campaign of kidnappings and killings since its self-proclaimed caliphate in Iraq and neighboring Syria collapsed in 2017.