A government official in Pakistan says President Pervez Musharraf must stand down in the next two days or face impeachment proceedings.
Foreign minister Shah Mahmood Qureshi, of the Pakistan People's Party (PPP) - a major partner in the governing coalition - said: "Musharraf is running out of time."
Draft charges against the president include violation of the constitution and gross misconduct.
Mr Musharraf's office has said he will not resign and will defend himself.
An impeachment campaign was launched last week by leaders of the PPP and the Pakistan Muslim League-Nawaz (PML-N), led by former prime minister Nawaz Sharif.
A PML-N official said there is a long list of charges against Mr Musharraf and they will file them, by "the latest, by Tuesday."
Mr Musharraf would be the first president in Pakistan's history to be impeached if he chooses not to quit.
Nawaz Sharif, who was toppled in the 1999 coup, said he was opposed to any deal which would give his old rival a "safe passage".
He has said the president should be tried for treason, which carries the maximum sentence of the death penalty.
But the PPP, the party of assassinated former Prime Minister Benazir Bhutto, says the decision of whether to put the president on trial should be left to parliament.