Parliamentary elections in Pakistan appeared set to be postponed by several weeks despite opposition demands they go ahead as planned on Jan. 8, officials said, setting up a new political standoff after Benazir Bhutto's assassination.

A Pakistani election official said Tuesday "it looks impossible" for the country to hold elections as scheduled in the wake of the violence that followed the assassination.

However, a final decision would not be made until Wednesday, after the Election Commission consulted all the political parties, commission spokesman Kanwar Dilshad said. Critics have said the commission is stacked with officials loyal to President Pervez Musharraf.

Former Prime Minister Nawaz Sharif, now the country's most prominent opposition leader, has threatened street protests if the vote is delayed. "We will agitate," he told The Associated Press. "We will not accept this postponement."

Western governments are urging the government to go ahead with the polls without major delays. They see the elections as a key step in U.S.-backed plans to restore democracy to the nation as it battles Taliban and al-Qaida militants.

White House spokesman Scott Stanzel said the government should set a specific date for new elections, but he said the timing was "up to the people of Pakistan."

Bhutto's party, now effectively controlled by her husband, and Sharif's opposition movement both feel they could be helped at the polls by widespread sympathy after Bhutto's killing last week at a campaign rally and accusations that allies of Musharraf had a role in the murder.

But political instability and the technical challenges of holding the vote after nationwide riots following the killing led to widespread expectations that the balloting will be delayed.

A senior government official predicted the elections would be postponed by "six weeks or so as the environment to hold free and fair elections is not conducive." The official spoke on condition of anonymity because he was not authorized to disclose the information.

Foreign election monitors cautioned that a full observation mission would be "impossible" if the polls went ahead next week because the unrest had disturbed their preparations. "We cannot follow our standard methods if the date stays Jan. 8," said Mathias Eick, a spokesman for the EU-led mission, saying the best it could manage was a limited "assessment" of the polls.

After days of rioting that left at least 44 dead, life in many Pakistani cities began returning to normal, though soldiers and police patrolled many areas.

The political uncertainty caused Pakistan's stock markets to tumble Monday, the first day of trading since the killing.

Sharif, who was toppled by Musharraf then exiled for seven years before his return to Pakistan in November, intensified his attacks on the U.S-backed former general, saying a free and fair vote would be impossible so long as he remained president.

"He is a one-man calamity," he said in his hometown of Lahore. "The United States should see that Musharraf has not limited or curbed terrorism. In fact terrorism is now stronger than ever before with more sinister aspects."

The United States had hoped that Bhutto, a liberal Muslim popular in the West, would become prime minister after the elections and enter into a power-sharing agreement with Musharraf — a combination seen as the most potent force against al-Qaida and Taliban militants in the country.

Sharif said if his party won the vote it would not work with Musharraf, suggesting any new government may be short-lived.

"You want me to work with such a man? He is the root cause of all the problems in the country," he said.

On Sunday, Bhutto's political party named her 19-year-old son, Bilawal Zardari, as its symbolic leader and left day-to-day control to her husband, Asif Ali Zardari, a former Cabinet minister accused of massive corruption during Bhutto's time as prime minister.

Zardari, who has accused Musharraf of responsibility for his wife's murder by failing to provide proper security for her, did not rule out the possibility of cooperating with the president if his party was in a position to form the next government.

"We will come to that position when we win the election," he told reporters.