Pakistani President Pervez Musharraf on Sunday faced a countdown to possible impeachment after the coalition government said he had until the end of the weekend to stand down.
Foreign Minister Shah Mehmood Qureshi said on Saturday that the key US ally had to make a decision on resigning to avoid being impeached "by today or tomorrow, as there is no room for any delay".
The coalition, led by the party of slain former prime minister Benazir Bhutto, also said it had finalised impeachment charges against Musharraf and would lodge them in Parliament early next week.
Talks between Musharraf's aides and the government aimed at securing him indemnity from prosecution have been hampered meanwhile by the opposition of Nawaz Sharif, another ex-premier.
Saudi Arabia and reportedly the United States and Britain have all sent envoys in a bid to resolve the crisis in the nuclear-armed nation, a frontline state in the "war on terror".
No president has been impeached before in Pakistan's 61-year history.
But Musharraf's spokesman has repeatedly insisted that the former army chief, who seized power in a bloodless military coup in 1999, has no intention of quitting.
Allies have said that he will defend himself against any charges.
Local newspapers said Musharraf was consulting legal advisers over challenging the impeachment move in the country's Supreme Court, which has been stacked with loyal judges since he purged it last year.
The News, a respected English-language daily, said there was a split between the attorney general and his legal aides over whether such a challenge could succeed.
The coalition is counting on independents and defectors from Musharraf's camp to win the two-thirds combined majority it would need in the upper and lower houses of parliament to impeach him.
Musharraf's other courses of action -- either dissolving the national assembly or imposing a state of emergency, as he did last November to stop legal challenges to his re-election -- are fraught with risk.
The support of the powerful army would be essential to take either step, and while analysts say the military wants to avoid the humiliation of his impeachment, army chief General Ashfaq Kayani has so far kept silent.
The United States has also taken a neutral stance, refraining from commenting on newspaper reports this week that Musharraf was on the verge of throwing in the towel.
"We've seen the press reports you're referring to, but these are all matters for the Pakistani political system and for the Pakistanis to deal with," said White House spokesman Gordon Johndroe on Friday.
Pakistan's rulers have however appeared divided since finally agreeing on August 7 to launch impeachment proceedings, following months of paralysis in the face of huge economic problems and Islamist violence.
Sharif, who was ousted in Musharraf's coup nine years ago then jailed for a year and sent into exile, said earlier this week that his arch-foe had violated the constitution and should get "no safe exit".
The government will be keen to resolve the impasse so it can deal with the fight against Taliban and Al-Qaeda militants in the tribal areas bordering Afghanistan, where nearly 500 people have died in the past week.
It also needs to tackle soaring inflation and widespread power cuts.
Analysts said the situation was being watched anxiously at home and abroad.
"The instability is of course causing concerns in Pakistan but it is also not in the interest of Pakistan's western allies," said Farzana Shaikh, a Pakistan expert at London-based think-tank Chatham House.