Police say a bomb blast has struck a major Shiite Muslim procession in Pakistan’s largest city of Karachi, where Shiites are marking the key holy day of Ashura.

Live television footage showed an explosion striking the procession on a main road, and ambulances were seen rushing to and from the scene.

Five persons are feared dead in the blast.

Police officer Raja Umer Khatab told The Associated Press that a bomb exploded, and that some in the crowd began firing shots into the air in protest.

Security has been tightened across Pakistan for Ashura, which is the 10th day of the holy month of Muharram, a month of mourning often marred by bombings and fighting between Pakistan’s Sunni Muslim majority and its Shiite minority.

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