Troops had to be deployed in cities across Pakistan as rioting protestors wrecked buildings and fought gun battles in the wake of Benazir Bhutto's assassination.
After she was laid to rest in the family mausoleum in front of a crowd of hundreds of thousands of mourners, mobs began blaming the government of President Pervez Musharraf for her death.
The government tried to calm the situation by saying they had "irrefutable evidence" from an intercepted message that al Qaida and the Taliban were responsible for the killing.
Ms Bhutto died on Thursday when a suicide attacker shot at her as she stood in the open sunroof of her vehicle and then blew himself up as she left a rally in Rawalpindi.
Authorities initially said she died from bullet wounds, but the interior ministry said that all three shots missed her.
Instead, she was killed when she tried to duck back into the vehicle, and the shock waves from the blast knocked her head into a lever attached to the sunroof, fracturing her skull. The cause for the discrepancy in the initial reports was not immediately clear.
The interior ministry spokesman said the government recorded an "intelligence intercept," in which militant leader Baitullah Mehsud "congratulated his people for carrying out this cowardly act".
He described Mehsud as an "al Qaida leader," and blamed him for the Karachi bomb blast that targeted Ms Bhutto in October and killed more than 140 people.
Mehsud is regarded as the commander of pro-Taliban forces in the lawless Pakistani tribal region South Waziristan, where al Qaida fighters are also active.
Meanwhile, Prime Minister Mohammedan Soomro said the government had no immediate plans to postpone parliamentary elections due on January 8, despite the growing chaos and a top opposition leader's decision to boycott the poll.
