Police in Pakistan tightened security today for the funeral of one of two prominent Sunni Muslim clerics whose murders on a busy Karachi street set off night-time riots by supporters, officials said.

Four people died and 16 others were injured when a bomb exploded near an Islamic school in Karachi, officials said.

GUNMEN killed a senior pro-Taliban cleric yesterday, sparking riots across the southern Pakistani city of Karachi by thousands of his Sunni Muslim supporters.

Gunmen riding in two cars and a motorcycle opened gun fire on a pick up truck carrying a senior Sunni Muslim cleric in the violence-prone Pakistani city of Karachi today, killing him and wounding four other people, police said.