Pakistan's president faces tough opposition after crushing defeat in elections.
Pakistani President Pervez Musharraf faced mounting calls to quit Tuesday as opposition parties moved towards a coalition government in the wake of a sweeping election victory over his allies.
The widower of slain former premier Benazir Bhutto said he had no interest in working with Musharraf's defeated backers, but said he would join forces with other groups opposed to the key figure in US anti-terror efforts.
"We will form a government of national consensus which will take along every democratic force," Asif Ali Zardari told a news conference a day after the parliamentary elections.
Celebratory gunfire erupted in several cities as unofficial preliminary results showed a big win for the parties of former premier Nawaz Sharif and of Bhutto.
"Musharraf has said he would quit when people tell him. People have now given their verdict," said two-time prime minister Sharif, ousted by Musharraf in a bloodless 1999 coup.
He said he was set to meet Zardari on Thursday.
Leading pro-democracy lawyer Aitzaz Ahsan, held under house arrest since Musharraf imposed a state of emergency in November, said the president should quit because he was the "most hated man in the country."
Several dozen protesters chanting "Go Musharraf, go!" gathered on Tuesday night outside the house of the country's deposed chief justice to protest his sacking by Musharraf in November and his continued detention.
Musharraf's spokesman bluntly rejected such calls and said the former general was willing to work with whoever forms a government.
"They are way off in their demands," spokesman Major General Rashid Qureshi told AFP. "This is not the election for president. President Musharraf is already elected for five years."
Unofficial results showed a rout of the pro-Musharraf ruling party, the Pakistan Muslim League-Q (PML-Q), placing the president at risk of a hostile parliament that, in theory, could seek his impeachment.
"We accept the verdict of the nation," said Tariq Azeem, a spokesman for the PML-Q, which backed Musharraf throughout the last parliament. "We officially concede defeat."
With votes counted in 258 out of 272 constituencies, the PPP and Sharif's party had a combined total of 153 seats, the election commission said. The PML-Q and its allies together had 58 seats.
The party's chief and several key members lost their seats in Pakistan's national assembly.
Results also showed a near total defeat for hardline Islamic parties that under the previous administration ruled Pakistan's North West Frontier Province bordering Afghanistan.
A team of US senators who monitored the vote said it was credible and legitimate. The opposition had feared polls would be rigged.
The White House said the elections were "largely fair."
"I think that what we can say is that they seem to have been largely fair and that people were able to express themselves, and that they can have confidence in their vote," spokeswoman Dana Perino said as President George W. Bush arrived in Ghana Tuesday on the fourth stop on his African tour.
In Washington, the State Department said Pakistan had taken a "step towards the full restoration of democracy."
UN chief Ban Ki-moon said he was encouraged by the "commitment of all parties concerned to respect the democratic process," his press office said.
The death of Bhutto in a December 27 gun and suicide attack - along with other suicide bombings - overshadowed the campaign and forced the election's delay until Monday.
Musharraf would become a powerless leader at best - and could lose his job - in the new political landscape, analysts said.
Observers said Musharraf would likely try to woo Bhutto's party and split it from Sharif's but said the president's need to fight for his own political survival would distract him from fighting terrorism.
Musharraf has been viewed by the United States as its bulwark in the fight against Al-Qaeda and Taliban militants based in Pakistan's tribal areas on the border with Afghanistan.
A spokesman for Afghan President Hamid Karzai said his country is looking forward "to fighting the root causes of terrorism" with Pakistan's newly elected representatives.
Japan hailed the elections as a step towards "stable democracy."
Investors also reacted positively, sending the Karachi Stock Exchange's main index 3.19% higher.
The election commission put turnout according to early results at about 45 percent - higher than in the previous two elections.