Masked gunmen on a motorcycle on Thursday shot dead a Shia cleric in Tank, a town already reeling from violence by pro-Taliban militants, police said. Ghulam Abbas, 50, was shot dead outside his home in Tank, police official Sultan Khan said. Police were searching for the assailants, who left their motorcycle behind and fled into a nearby forest, Khan told AFP. Abbas was in charge of a local mosque, he said, adding that the killing appeared to be linked to sectarian rivalry. Shia account for about 20 percent of PakistanÂ’s 160 million Sunni-dominated population.