"We have increased the presence of Rangers in the city and have told them to arrest or shoot anyone involved in violence and riots threatening life or property," Syed Kamal Shah, the interior secretary told Reuters, referring to a paramilitary force.
"The events of yesterday were very serious and violent. The whole city was paralysed and many precious lives lost...We don't want a repeat."
"It would be in the best interests of Pakistan for Musharraf to step down"
Jim ibarra, Cyberjaya, Malaysia
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Violence flared on Saturday when rival rallies timed for a visit to Karachi by Iftikhar Chaudhry, the country's suspended chief justice, developed into gunfights and clashes between rival political activists.
Government attempts to remove Chaudhry over unspecified accusations of misconduct on March 9 have outraged the judiciary and the opposition and has evolved into a campaign against Pervez Musharraf, the Pakistani president.
Kamal Hyder, Al Jazeera's correspondent in Islamabad, said further violence could occur as government supporters planned to hold a rally in the capital and further burials of the victims in Karachi took place.
Musharraf condemned the violence in a speech at a rally of his supporters in Islamabad late on Saturday.
But he ruled out declaring a state of emergency saying the people were with him. Elections due late this year would be held on time, he said.
It is the most serious challenge to the authority of the president, who is also army chief, since he seized power in 1999.
A spokesman for the Pakistan Peoples Party of Benazir Bhutto, a former prime minister, blamed Musharraf and the pro-government Mutahida Qaumi Movement party for the violence.
"We therefore hold the federal government and Musharraf equally responsible for what has happened. It shows that the government wanted to create a situation of civil strife to find an excuse for imposing an emergency and postponing the elections," he said.
On Sunday, Tariq Azeem Khan, the information minister, said it was too early to say who was responsible for the "carnage".
He said there was no "definite proof" of who was involved in the rioting and that the prime minister and the provincial government have ordered separate inquiries.
The exiled leader of the MQM, Altaf Hussain, blamed Chaudhry for the violence, saying he should have heeded warnings from officials to stay away from Karachi. He said it was the MQM that was attacked.
The MQM is a coalition partner in both the government of Sindh province, of which Karachi is the capital, and the federal government. The Karachi-based party has a reputation for militancy.
In December 1986, 90 people were killed in violence between ethnic Pashtuns and MQM supporters.