Benazir Bhutto's 19-year-old son — a student with no political experience — was named symbolic leader of her party Sunday, while her husband took effective control, extending Pakistan's most enduring political dynasty.

The major parties appeared to agree that the elections should take place as scheduled on Jan. 8 despite street violence and political turmoil triggered by the assassination of Bhutto. The Election Commission was to discuss the timing of the polls Monday.

A successful vote would bolster U.S.-backed plans to restore democracy to the nuclear-armed country as it battles rising Islamic extremism. However, video footage of Bhutto's killing threatened Monday to further undermine confidence in the Pakistani government by raising new questions about its version of how she died.

The footage, obtained by Britain's Channel 4, shows a man firing a handgun at Bhutto from close range as she stands up in an open-topped vehicle. Her hair and shawl then move upward, suggesting she may have been shot. She then falls into the vehicle just before an explosion rocks the car.

The government has insisted Bhutto was not hit by any of the bullets and died after the force of the blast slammed her head against the sunroof. Bhutto's family and supporters say she died from gunshot wounds to her head and neck.

Rioting subsided Sunday after destruction that left at least 44 dead and caused tens of millions of dollars in damage, but bitterness remained over the government's response to the Thursday attack on Bhutto.

Bhutto's husband, Asif Ali Zardari, said late Sunday he refused permission for doctors to perform an autopsy, meaning that short of exhuming her body — something her supporters have already ruled out — the cause of her death will be difficult to establish.

The appointment of Bhutto's husband was not without its own complications. A former Cabinet minister who spent eight years in prison on corruption accusations, he is known as "Mr. 10 Percent" for allegedly taking kickbacks and is viewed with suspicion by many Pakistanis.

At a news conference on Sunday, Zardari said the opposition party — Pakistan's largest — had no confidence in the government's ability to bring the killers to justice and urged the United Nations to establish a committee like the one investigating the 2005 assassination of former Lebanese Prime Minister Rafik Hariri.

The decisions on the future of Bhutto's Pakistan Peoples Party were made at a closed-door meeting in the sprawling family estate in the south of the country where the two-time former prime minister grew up.

The eldest of Bhutto's three children, Bilawal Zardari, accepted the party's leadership, but said he would remain at Oxford University. He said his father, who was officially designated co-chairman, would be the effective party leader.

"The party's long struggle for democracy will continue with renewed vigor," Bilawal told a news conference that was repeatedly interrupted by emotional chants from Bhutto's supporters. "My mother always said democracy is the best revenge."

Bhutto's grandfather was a senior figure in the movement that helped Pakistan split from India and lead it to independence in 1947. Her father — Pakistan's first elected prime minister — founded the Pakistan Peoples Party in 1967 and its electoral success since then has largely depended on the Bhutto name.

Bilawal said that Zardari would "take care" of the party while he continued his studies. Zardari then told reporters to direct questions at him, saying his son was at a "tender age."

Zardari, who spent eight years under detention on corruption charges in Pakistan before his release in late 2004, is a power broker who served as investment minister in Bhutto's second government. He has denied the graft charges.

He immediately announced the party's participation in the elections, perhaps sensing sympathy for Bhutto and her family could translate into a strong performance in the polls, but said another party leader, Makhdoom Amin Fahim, would likely be their candidate for prime minister if they won.

He also appealed to the party of former Prime Minister Nawaz Sharif to reverse an earlier decision to boycott the polls. Sharif's party later agreed.

"It is up to the political parties in Pakistan to choose their leaders," White House spokesman Scott Stanzel said from Crawford, Texas, where President Bush is vacationing.

"We believe it is important for Pakistan to confront extremists and continue on the path to democracy by holding free and fair elections," he said. "The timing of those elections will be up to the Pakistanis."

Tariq Azim, a spokesman for the pro-government Pakistan Muslim League-Q party, congratulated the decision to against seeking a delay in the vote.

"We welcome it, and we are also ready for the contest on Jan. 8," he said after earlier predicting the election may be delayed up to four months.

The British and U.S. governments had been pushing Bhutto, a moderate Muslim seen as friendly to the West, to form a power-sharing agreement with President Pervez Musharraf after the election — a combination seen as the most effective in the fight against al-Qaida, which is believed to be regrouping in the country's lawless tribal areas.

But many of her supporters have alleged that political allies of Musharraf were behind her killing, which the government has blamed on Islamic militants with links to al-Qaida.

A statement from the British government said Musharraf had agreed to consider "potential international support" to the Pakistani investigation into the assassination, but gave no more details. It also urged Pakistan to go ahead with elections without any "significant delay."

Zardari has rejected as "lies" the government's account of how his wife died. No fresh rioting was reported Sunday and Zardari urged supporters to show restraint.

"God willing, when it is the Peoples Party's reign, when the Peoples Party government is formed, then we would have taken revenge for Bibi's blood and that blood would not have gone waste," Zardari said, referring to his late wife by her nickname.

• Click here to view photos.

Click here to read FOX News' Jennifer Griffin's on the scene blogs from Pakistan.

Bhutto's Pakistan Peoples Party central executive committee met privately to choose her successor three days after the two-time prime minister was assassinated in a suicide attack that thrust the volatile Islamic nation deeper into crisis.

Her son, Bilawal Zardari, a student with no experience in politics, said he would remain at Oxford University, leaving his father, Asif Ali Zardari, who was officially designated co-chairman, as the effective leader of the country's largest political party.

"The party's long struggle for democracy will continue with renewed vigor," Bilawal told a news conference. "My mother always said democracy is the best revenge."

Supporters chanted "Benazir, princess of heaven" and "Bilawal, move ahead. We are with you."

Bhutto's grandfather was a senior figure in the Pakistan Muslim League, the party that helped Pakistan split from India and lead it to independence in 1947. Her father — Pakistan's first elected prime minister — founded the party in 1967 and its electoral success since then has largely depended on the Bhutto name.

Bilawal said that Zardari would "take care" of the party while he continued his studies. Zardari then told reporters to direct questions to him, saying his son was at a "tender age."

Zardari, who spent eight years under detention on corruption charges in Pakistan before his release in late 2004, is a party powerbroker who served as environment minister in Bhutto's second government. He has denied the charges of large-scale graft during his wife's rule.

He immediately announced the group's participation in the elections but said another party leader, Makhdoom Amin Fahim, would likely be their candidate for prime minister if they won.

Zardari appealed to the party of former Prime Minister Nawaz Sharif to drop plans to boycott the polls. Sharif's party later agreed to the appeal and said it would take part in the elections.

Some people have called for a delay in the elections given the turmoil in the country following Bhutto's killing, but a senator from her party said it was demanding that they take place on time.

"We want elections on Jan. 8 and we will not let the government run away from the elections," said Sen. Safdar Abbasi.

The government has blamed an Al Qaeda-linked militant for the murder of Bhutto but her party disputes that and claims elements in the Pakistan Muslim League-Q — the ruling party that supports President Pervez Musharraf — could have been behind the slaying.

Zardari repeatedly called the ruling party the "killer league."

He also rejected as "lies" the government's account of how his wife died, amid a dispute over whether she sustained fatal gunshot wounds or was killed by the force of the suicide blast that struck her vehicle as she left a campaign rally on Thursday.

Bhutto was buried without an autopsy and the debate over her cause of death has undermined confidence in the government and further angered her followers.

Zardari appealed to the United Nations and British government to help investigate the crime. He said the party wanted a U.N. investigation like the one probing the 2005 assassination of former Lebanese Prime Minister Rafik Hariri. The government has already said international involvement in the investigation is not necessary.

The killing triggered violence throughout Pakistan but there was no fresh rioting reported Sunday.

Since Thursday, unrest has killed at least 44 people and caused tens of millions of dollars of damage. Rioters have destroyed 176 banks, 34 gas stations, 72 train cars, 18 rail stations, and hundreds of cars and shops, the government says.

They have also wrecked nine election offices — along with the voter rolls and ballot boxes inside — hampered the printing of ballot slips and the training of poll workers, the election commission said. The commission has called an emergency meeting for Monday.

Zardari urged supporters to show restraint.

"We will avenge the murder of Bhutto through the democratic process after winning the elections," he said.

"God willing, when it is the Peoples Party's reign, when the Peoples Party government is formed, then we would have taken revenge for Bibi's blood and that blood would not have gone waste," Zardari said, referring to his late wife by her nickname.

In fresh militant violence, two men blew themselves up Sunday near the residence in eastern Pakistan of Ijazul Haq, the former religious affairs minister and senior leader of the ruling party, said district police chief Zafar Abbas Bukhari. Both men died, but there were no other casualties.