Pakistani authorities on Friday issued shoot-at-sight orders and ordered deployment of 1,000 additional paramilitary troops in Karachi as vicious violence continued to paralyse the country's financial capital, leaving nearly 95 people dead in last four days.

Interior Minister Rehman Malik said that security forces had been given orders to shoot gunmen on sight to meet the challenge. The violence has rocked the country's financial hub and continued on Friday although a total shutdown was observed in the city on the call for a day of mourning by the Mutahida Qaumi Movement (MQM) for the people killed in the violence.

Rockets were fired and grenades lobbed as violence wracked the city with thousands of people stranded in their home in fear of flying bullets. The violence also escalated after President Asif Zardari issued orders to restore the commissioner's system in the city.

Police and rescue officials said that in four days 95 people had been killed with some 200 wounded in target killings and indiscriminate firing in many parts of the city, owing to political as well as ethnic clashes. The decision to restore the commisioner's system was taken at a high level meeting in Islamabad, which also proposed amendments to the local bodies system.

The MQM leadership said it opposed this decision and senior member Raza Haroon said that MQM will oppose it in the assembly. Struck by the magnitude of incidents in Karachi, the US Embassy in Islamabad on Friday said it is deeply concerned about the escalating violence in the port city.

"We call on all parties to refrain from further violence and work toward a peaceful resolution of differences," Ambassador Cameron Munter said in a statement. "The loss of...lives, including women and children, in the last three days is a tragedy."

Karachi has been rocked by violence despite the presence of President Asif Zardari in the city where he is stationed at the Bilawal house and has held meetings with his aides to discuss the situation.

Interior Minister Rehman Malik, who rushed to Karachi on Thursday, said that 1,000 additional militia force will be deployed to restore normalcy in the city. Malik admitted that security forces faced challenges in some areas due to power outages.

"There is someone who is trying to destabilise Pakistan," the minister said and added that he believes all political parties have realised that there is indeed a ‘third force’ behind the violence.

He also said that ‘targeted actions’ will be taken against the miscreants without any political discrimination. "We have received satellite images about those who have made bunkers and actions are being planned against them," Malik told reporters in Karachi where he attended a meeting of senior police and paramilitary military commanders.

Meanwhile, the city gave a deserted look as the main powerful ethnic group declared mourning over the recent wave of violence. Public transport is missing and people faced problems to find transport to reach offices, residents said.

President of the transport union, Irshad Bukhari, said that transporters had decided not to bring vehicles as the MQM had declared mourning. "Several vehicles had been burnt, buses hijacked and divers killed," Bukhari said, adding, "We can not run buses in this situation.