Karachi was in mourning a day after the deadly suicide attack on a Muharram procession in which the death toll has now climbed to 43.
Despite the incidents of widespread arson following the bombing, the situation remained under control.
But until late into the morning, fire engines continued to battle flames in properties that were set ablaze by rioters after the bombing.
The provincial government declared on Tuesday a holiday and designated it as an official day of mourning for the dead.
Shops, businesses, schools and petrol pumps remained closed and there was no public transport as the city prepared for the funerals of those who were killed in the attack.
Hundreds of shops were burnt in Monday’s arson spree following the suicide attack. Interior minister Rehman Malik, who visited Karachi on Tuesday, said the incidents of violence were a “pre-planned” conspiracy to engulf the city in flames.
He said it was improbable the Shia mourners in the processions were carrying jerry-cans of petrol ready to torch properties.
The fires began within minutes, and this, Mr. Malik said, pointed to a conspiracy against Pakistan.
He promised that the government would compensate traders for the losses, which may be run into billions of rupees.
Police officials said they were studying CCTV footage of the bombing. The bomber is said to have used 16 kg of explosives.
Earlier, the police issued a photograph of a severed head discovered from the site of the attack, thought to belong to the bomber, but it was later discovered to be that of a mourner in the procession.
This was the first major terror attack in Pakistan’s financial hub in over two years.