Pakistan's biggest city and financial center Karachi nearly shut down on New Year's day as political and religious leaders called for a strike to protest against violence after a suicide bomber killed 43 people at Ashura procession staged by Shiite Muslims on Monday.

Karachi's streets were nearly empty on Friday. Markets and shops as well as the stock exchange were closed.

Police have arrested 18 people since riots triggered by the bomb blast destroyed Pakistan's biggest wholesale market, costing an estimated 40 billion Pakistani rupees (500 million U.S. dollars) in damages.

Pakistani Taliban claimed responsibility for Monday's attack and threatened more attack in retaliation for government crackdown on the militant group in northwest trial areas near the border with Afghanistan.