NAUDERO, Pakistan (CNN) -- Pakistan's Central Election Commission said Monday that a decision is expected Tuesday on whether to hold parliamentary elections as scheduled on January 8.
In a video released Sunday, Benazir Bhutto, far right, appears through the sunroof before shots ring out.
Election Commission Secretary Kanwar Dilashad denied media reports that the commission had already sent recommendations to the government recommending postponement.
Meanwhile opposition leader and former Pakistani Prime Minister Nawaz Sharif announced Monday that his Pakistan Muslim League-N party will participate in elections.
Sharif's party had initially said it would boycott the vote to "express our solidarity" with former rival, Benazir Bhutto, following her assassination last week -- but Bhutto's husband, Asif Ali Zardari, Sunday called on Sharif to participate.
"Now that they've appealed to us to participate, they've also decided to participate in the elections," said Sharif. "So our party considered the appeal that they have made to us and ... have decided to contest the elections."
He said he believes President Pervez Musharraf plans to delay next week's vote because his party will not garner enough seats to rule.
The political developments came hours after dramatic new videotape of the assassination of former Pakistan Prime Minister Benazir Bhutto emerged, showing her slumping just after gunshots ring out.
The tape provides the clearest view yet of the attack and appears to show that Bhutto was shot. That would contradict the Pakistan government's account. Watch new tape showing apparent gunman »
A previously released videotape shows a man at the right of her vehicle raising a gun, pointing it toward Bhutto, who is standing in her car with her upper body through the sunroof. He fires three shots. Then, there is an explosion.
In the video that emerged Sunday, Bhutto is standing, and her hair and scarf appear to move, perhaps from the bullet. Bhutto falls into the car. Then, the blast.
These images seem to support the theory that Bhutto died at the hands of a shooter before a bomb was detonated, killing another 23 people.
Everyone inside Bhutto's bomb-proof car lived. Those traveling with her say they saw her bleeding, and the heavily blood-stained interior appears to support their accounts. See the likely sequence of events »
The doctor who initially examined the body said Bhutto died of bullet wounds. However, the Pakistani government later said she died from shrapnel wounds from the explosion.
And, in a move that caused more confusion, the government released X-rays of Bhutto's skull and said they show she died when the force of the explosion caused her head to slam into a metal lever on the sunroof.
But Zardari, disputed the government's account. "I can say confidently that she was shot," he said.
He called the government's explanation "a useless excuse, because they have to divert attention from the main subject" -- who is responsible for the killing.
Zardari also said the parliamentary elections should not be postponed.
"Our demand is elections on time -- free, fair as promised," he said Sunday.
Election commission officials said delaying their decision until Tuesday allows the group to gather information from provincial election commissions and consider "law and order situations."
Dilashad said he will receive reports from Pakistan's four provinces on Monday regarding law and order, as well as recommendations regarding the timing of elections.
Bhutto's death was followed by widespread violence and the destruction of many local election offices, which may give the commission cause for postponement. It is scheduled to meet again on Tuesday at 9 a.m. (11 p.m. ET Monday).
Zardari said he will serve as co-chairman of the Pakistan People's Party while their 19-year-old son, Bilawal, and newly named heir to the party leadership, finishes his studies.
"He will, of course, be kept aware of all that is happening with the party," Zardari told CNN sister network CNN-IBN. "I will be looking after the interests of the party, as a guide, as a helper, and as a friend to the party, and as a part-time leader."
Once the political science student at Oxford University has been properly groomed, "then I can go and play golf," Zardari said.
Zardari acknowledged that his wife stipulated in her will that he was to step into her role in the event of her death. But Zardari said his decision to pass that role to their son is correct.
"I, in my political wisdom, think we need a larger symbol than myself to keep the party united with her gone," he said. "Because she could have probably not even herself imagined the reaction that her death would do to Pakistan."
He said Bhutto's assassination on Thursday has thrust Pakistan onto the verge of disintegration.
Zardari said he does not trust the government led by President Pervez Musharraf to ensure the elections are indeed free and fair, but he does believe the people of Pakistan will be able to ensure that happens.
Whether his other two children will decide to enter politics "is entirely up to them," he said.
He said Bhutto had trained Bilawal: "He realizes the enormity of the situation. So therefore, he's accepted the responsibility." Watch Bhutto's son and husband talk about the party's future »
The teenager, speaking in English at a news conference, said, "My mother always said democracy is the best revenge."
"Like all chairmen of the PPP, I will stand as the symbol of the federation," said Bilawal Bhutto. "The party's long and historic struggle for democracy will continue with renewed vigor, and I stand committed to the stability of the federation." Watch Human Rights Watch official explain son's important symbolic role »
British Prime Minister Gordon Brown spoke to Musharraf on the telephone Sunday, and the Pakistani leader agreed to consider international support for the investigation into Bhutto's death, according to a statement from Brown's office.
Musharraf's government has previously rejected international help, specifically from Britain.
"We understand our environment better than the international community," Pakistani Interior Ministry spokesman Javed Iqbal Cheema said Saturday.
"Scotland Yard cannot investigate in Waziristan. They don't understand Pashto."
Zardari also said the PPP is asking the United Nations to investigate the circumstances of Bhutto's December 27 killing. He said he does not plan to call for an autopsy on his wife, who was buried in her hometown on Friday.
Musharraf also spoke Sunday with French President Nicolas Sarkozy, a French foreign ministry spokeswoman told CNN. After the conversation, it was announced that French Foreign Minister Bernard Kouchner will travel to Pakistan this week.
When asked about the naming of Bhutto's successor, White House spokesman Scott Stanzel said, "It is up to the political parties in Pakistan to choose their leaders." E-mail to a friend
CNN's Ali Velshi and Zain Verjee contributed to this report.