LAHORE, Pakistan: The most experienced opposition politician left in Pakistan, former Prime Minister Nawaz Sharif, sharpened the battle lines with President Pervez Musharraf on Monday, calling for his immediate resignation and the formation of a government of national consensus.

In delivering his most stinging public attack on Musharraf since returning from exile, Sharif said the president "must immediately resign" following last week's assassination of Benazir Bhutto, the other leading opposition leader.

"He is a one-man calamity and the source of all the problems," Sharif said of Musharraf at a news conference here, the headquarters of his faction of the Pakistan Muslim League. "The country is burning."

Sharif also said that if parliamentary elections went ahead on Jan. 8 as scheduled, his party, a faction of the Pakistan Muslim League, would participate even though he had said three days ago that his party would boycott them.

Both Sharif's party and the Pakistan Peoples Party, now led by the son and the husband of Bhutto, believe they can capitalize at the polls on the deep well of sympathy for her and the anger against the government in the wake of her assassination.

But Sharif emphasized that if the Election Commission of Pakistan went ahead with polling next week, the results could not be free and fair.

Many opposition figures and Pakistani political analysts have contended that the elections would be flawed if they were held on Jan. 8 because of damage at election offices in Sindh Province caused by the violence that erupted after Bhutto's death, the burning of electoral rolls and the government's reported plans to rig the results.

Sharif suggested his party would be participating in the elections because it had little choice but to follow the decision of Bhutto's party on Sunday to participate.

The election commission of Pakistan said Monday that it would wait until Tuesday to make a formal decision on whether to move ahead with voting on Jan. 8, a date that Washington has pushed the government to keep.

Election officials said the voting would probably be delayed until the end of January or early February in order to remedy the chaos at the electoral offices in Sindh.

Considerations on a fresh date would be determined so as to avoid holding the election clash during the annual religious festival of Muharram, which is observed by Shiite Muslims during much of January, the officials said.

Opposition politicians said it was in the government's interest to delay the elections so it could try to recoup support that it lost after the assassination of Bhutto. Many Pakistanis have said they blame the Musharraf government for her death because its security agencies failed to provide proper protection for Bhutto as she left a rally at the garrison city of Rawilpindi.

The strong words by Sharif against Musharraf reflected the poisonous history between the two men.

Like Bhutto, Sharif was twice prime minister. He was deposed during his second term in October 1999 when Musharraf was head of the Pakistani Army and staged a coup against him.

Hours before the coup, Sharif had hoped to oust General Musharraf — whom Sharif had personally elevated to the top army post — by trying to prevent his plane from landing after a trip abroad.

Once Musharraf became president, he charged Sharif with attempted murder and corruption, then banished him to a 10-year exile in Saudi Arabia.

Sharif returned to Pakistan last month after Musharraf failed to persuade the Saudi government to keep him there.

Ever since his return, Sharif has taken a tougher stand against Musharraf than Bhutto, including a demand that the president restore the judges of the Supreme Court and High Courts who were fired on under the recent six week emergency rule.

Expanding on Sharif's comments at the news conference here, his brother, Shahbaz, also an experienced politician, said he was confident that the mood against the Musharraf government had turned so sour that the two main opposition parties would win the election, even if it was delayed a bit.

Shahbaz Sharif was chief minister of Punjab province, one of the most powerful jobs in Pakistan, during the second term of Nawaz Sharif.

"The Pakistan People's Party will win seats, and we will seats and defeat the Q League hands down," he said, referring to the faction of the Pakistan Muslim League that holds Musharraf's followers. "Even if they try to rig we will win. The atmosphere has changed against them. The courage to rig has diminished."

Shahbaz Sharif accused the current chief minister of Punjab, Chaudhry Pervaiz Elahi, of planning to distribute forged ballot papers and to create "ghost" polling stations in order to swing the election in favor of Musharraf's party.

"Ghost" polling stations are extra polling places that are often created in Pakistani elections to enhance vote totals of one side or another.

Shahbaz Sharif sounded a confident tone that his party would prevail over Chaudhry's faction of the Pakistan Muslim League that is the party of Musharraf, and that he would have the power as he did as chief executive of Punjab to punish. "We've given them a stern warning that if they monkey with the elections I will treat them according to the law of the law," he said. "People will be held accountable."

The best solution to the current fraught political atmosphere, Shahbaz Sharif asserted, would be for Musharraf to allow a government of "national consensus" to be formed in consultation with the opposition parties. This government's chief task would be to prepare the elections 45 days to three months after taking office.

The new government could form a neutral and powerful election commission to replace the current politically biased one, a move that was more likely to ensure free and fair elections, he said. "The Election Commission is a pawn, it has no legitimacy," he said.

Such a government would also be in a position to better investigate the circumstances surrounding the assassination of Bhutto because it would be perceived as being more neutral, he said.

The idea of a consensus government that would hold office until new elections has gained currency in Pakistan's news media since the death of Bhutto.

If steps were not taken to form a consensus government , Sharif said he believed the public anger could spin out of control.

The fury in the province of Sindh, the home base of the Bhutto family, was so intense that it was possible the province could hive itself off as a separate entity. There were strong undercurrents for separation from the federation of Pakistan in the province of Baluchistan and North West Frontier Province as well, he said.

"The international community must see that Pakistan can sink into deep turmoil," he said. In order to stave off the potential chaos, the international community could use pressure on Musharraf in ways that had been successful to persuade to step down as army chief and to end the six-week emergency rule imposed last month, he said.

"If Benazir Bhutto's killing is not investigated fairly and elections are not free and fair, and if a neutral caretaker government is not put in place, it can lead us to a crisis beyond anyone's reach."