Pakistan was on Saturday gripped by division and uncertainty following the burial of slain opposition leader Benazir Bhutto as her supporters angrily rejected a government explanation of her death.
One day after Bhutto was laid to rest at her family's mausoleum in southern Sindh province, the authorities used force to stem violence which has left at least 33 people dead in the nuclear-armed nation since her killing.
The army has deployed 16,000 troops in areas of her Sindh stronghold while paramilitary forces in the southern port of Karachi, Pakistan's largest city, have been given authority to shoot on sight.
As the United States and other Western nations pressured Pakistan to go ahead with general elections on January 8, a bitter dispute was erupting over how the former premier died and who was to blame.
Bhutto died on Thursday shortly after a suicide attack targeting her vehicle at a campaign rally in the northern city of Rawalpindi. Early reports said she had been shot before a bomb exploded nearby.
However the interior ministry said late on Friday she had no gunshot or shrapnel wounds. It said she died after smashing her head on her car's sunroof as she tried to duck.
Interior ministry spokesman Brigadier Javed Cheema said Bhutto would have survived the latest assassination attempt if she had stayed inside the car and not had put her head above the sunroof.
He also blamed Al-Qaeda, saying intelligence services had intercepted a call from Baitullah Mehsud, considered the extremist group's top leader for Pakistan, congratulating a militant for Bhutto's death.
However Bhutto's Pakistan People's Party rejected the government's findings as a "pack of lies", and said two party officials were inside Bhutto's vehicle during the attack and saw what happened.
"Two bullets hit her, one in the abdomen and one in the head," Farooq Naik, Bhutto's lawyer and a senior PPP official told AFP. "It is an irreparable loss and they are turning it into a joke with such claims," he said, warning that the country could be heading towards civil war.
Bhutto was an outspoken critic of Al-Qaeda-linked militants blamed for scores of bombings in Pakistan and had received death threats.
But she had also accused elements from the intelligence services of involvement in a suicide attack on a Bhutto rally in October that left 139 dead and which she only narrowly escaped.
Analysts warned that Pakistan was facing the biggest crisis since Bangladesh split off from the country more than 35 years ago, and that President Pervez Musharraf's credibility was hanging by a thread.
"We are heading towards a very uncertain phase of politics which has the potential to plunge the country into a state of anarchy," Hasan Askari, former head of political science at Lahore's Punjab University, told AFP.
A national strike called by the opposition on Friday turned Karachi, normally a bustling metropolis of 12 million people, into a virtual ghost town, with taxis and buses off the roads and many residents too afraid to venture outdoors.
Among the incidents, police said, six people were burnt to death in a leather factory in Karachi when a mob set it ablaze.
The scale of the unrest has paralysed Pakistan, setting off alarm bells around the world and raising serious doubts about whether the parliamentary elections aimed at ending eight years of military rule can take place.
Pakistan's other leading opposition figure, Nawaz Sharif, has already pulled his party out of the elections, saying they would "destroy the country" if they went ahead.
The assassination has also thrust security concerns and foreign policy back into the US political spotlight less than a week before Americans start voting to decide their Democratic and Republican presidential candidates.
Leading democratic candidate Hillary Clinton called for an independent, international probe into Bhutto's murder, saying Musharraf's government had no credibility.
"I think it's critically important that we get answers and really those are due first and foremost to the people of Pakistan," Clinton said.
Hundreds of thousands of grief-stricken mourners followed Bhutto's coffin on the final journey to the Bhutto family's mausoleum in the village of Ghari Khuda Bakhsh on Friday.
Bhutto's husband Asif Zardari wept as the coffin with the body of the 54-year-old opposition leader was lowered into the tomb where she will lie next to her father, former premier Zulfikar Ali Bhutto who was hanged by the military government in 1979.
Benazir Bhutto, who was educated at Harvard and Oxford, first took the helm of Pakistan in 1988. She was ousted in 1990 amid corruption allegations but was premier again from 1993 to 1996.