Pakistan President Pervez Musharraf, under pressure to step down before he is impeached, will address the nation on Monday.
The country's ruling coalition has prepared impeachment charges against Mr Musharraf, accusing him of violations of the constitution and misconduct.
Most analysts expect the former army chief to resign soon, perhaps before impeachment proceedings begin, or after defending himself against the accusations.
Mr Musharraf, 65, came to power in a 1999 coup.
The Pakistan People's Party of assassinated former prime minister Benazir Bhutto leads the coalition, with former prime minister Nawaz Sharif's Pakistan Muslim League its main partner.
The two main civilian parties are old rivals and, despite recent co-operation, will compete in the next election.
Mr Musharraf has authority to dismiss parliament and make top military and judicial appointments. The coalition vows to strip the presidency of those powers and make it a largely ceremonial post.
However, analysts say Ms Bhutto's widower, Asif Ali Zardari, may want the job, in which case he will want to keep the powers. However, Mr Zardari has suggested that the next president might be a woman.
Newspapers have speculated that an ethnic Pashtun leader, Asfandayr Wali Khan, whose liberal party is part of the coalition, may get the job. The president is elected by the four provincial assemblies and the national parliament.
