Pakistan's electoral commission has delayed its decision on whether to put back elections planned for 8 January.
The violent unrest which has followed the assassination of Benazir Bhutto has put the election date in doubt.
Her widower, Asif Ali Zardari, said her Pakistan People's Party would contest the poll. He and his son, Bilawal, will take over the leadership of the party.
Pakistan's stocks fell by 4.7% as they resumed trading after three days of mourning following Ms Bhutto's death.
The ruling PML-Q party has said the January 8 vote should be delayed for several weeks, on the grounds that the vote would "lose credibility" if held under current conditions.
But the PPP says it wants the elections to go ahead as planned and the other main opposition party, led by Nawaz Sharif, has indicated it will also drop plans to boycott the election.
If the election does go ahead, it is not clear who the PPP would propose as prime minister.
At 19, Bilawal is legally too young to stand for parliament.
And his father has been repeatedly accused of corruption - though he denies the charges and has never been convicted in court.
Mr Zardari said PPP vice-chairman Makhdoom Amin Fahim would probably be its candidate for prime minister.
Bilawal was chosen to take over the PPP leadership from his late mother at a meeting in the party stronghold of Naudero, near Larkana in the south of the country.
Bilawal, who will be a titular head while he finishes his studies at Oxford University, said: "My mother always said democracy is the best revenge."
Mr Fahim said Mr Zardari had been named party chairman, but had turned down in favour of his son - a decision Mr Fahim said the party leadership had endorsed.
Mr Zardari also announced that the couple's children would now change their names and be called Bhutto Zardari.
Mr Zardari added that he had refused to allow an autopsy on Ms Bhutto's body.
"I've lived here long enough to know how and where an autopsy would have been conducted," he said.
Instead, he said the party was asking the United Nations and the British government to conduct an investigation similar to the one carried out after the killing of the former Lebanese Prime Minister Rafik Hariri.
And he appealed for an end to the unrest in Pakistan, which has killed at least 38 people since Ms Bhutto's killing.
British Prime Minister Gordon Brown also called for calm in the country and stressed the importance of holding free elections, in an article for Pakistan's Daily Jang newspaper.
"A strong representative democracy in Pakistan will defeat terrorism and extremism, show the path to a more stable, prosperous future, and stand as a lasting memorial to the life's work of Benazir Bhutto," he wrote.
Earlier, Pakistani television released new pictures it said showed Ms Bhutto's attackers - a gunman and a suicide bomber. They also apparently showed Ms Bhutto was inside her car, and no longer standing through the sun roof, when the explosion happened.
The images added to the dispute over Ms Bhutto's death.
Interior ministry spokesman Brig Javed Iqbal Cheema said on Friday that she was killed when the force of the bomb blast knocked her head against a sun roof fitting, and was not hit by bullets.
The PPP has insisted she was killed by two bullets, one of which pierced her skull and another which hit her in the neck. ( BBC )