Security forces in the Pakistani city of Karachi have been ordered to shoot at sight anyone involved in violence on the spot. More than 80 people have been killed since Tuesday in unrest widely blamed on armed gangs from rival political parties. Pakistan’s biggest city of Karachi is virtually shut down. Many shops, schools and offices are closed and there is hardly any traffic on the streets. Most people are staying at home fearing more violence. The government says it has deployed an extra 1,000 troops. Interior Minister Rehman Malik said that most of those who had died were innocent people. He said very few are politically affiliated people. Mr. Malik added that 89 people had been arrested for involvement in the violence. Karachi’s main political party, the MQM, which resigned from the government last week, has called for a day of mourning.