Bhutto will land in southern Pakistan's port city of Karachi, where she will pay tribute to a mausoleum of the nation's founding father Mohammad Ali Jinnah, the PPP said at a press conference telecast live by local TV channels.

Bhutto, leader of PPP, a major opposition party, served twice as prime minister of Pakistan in the late 1980s and mid-1990s, and went into a self-imposed exile in 1999 to evade corruption charges against herself and her family.

General Pervez Musharraf's term as president will expire on Nov. 15, with government officials saying the presidential elections will be held between Sept. 15 and Oct. 15.

According to Pakistan's constitution, the election to the office of president shall be held not earlier than 60 days and not later than 30 days before the expiration of the term of the president in office.

Chief Election Commissioner Qazi Muhammad Farooq Tuesday said that schedule for the presidential polls will be announced in a few days.

Seeking to renew his presidential term, President Musharraf, who gained power in a 1999 military coup, has been holding talks with Benazir Bhutto for a possible reported "power-sharing" formula.

But no deal has been finalized yet, according to public statements from both sides.

Bhutto is reportedly asking Musharraf to cancel the accusations against her, remove the legal bar for the former prime minister to go for a third term, and shift power of dissolving assemblies from president to prime minister. Bhutto also reportedly demanded Musharraf to quit post of army chief, the country's top military leader.

In return, PPP, a national party with alleged high popularity in Pakistan, will offer cooperation to Musharraf during his efforts to get re-elected as president, earlier reports say.

Bhutto has been vowing to lead her party's campaign during the coming parliamentary elections, which will be held by January 2008, within three months following the expiry of current assemblies' term in mid-October this year.

Upon this report's releasing, there has been no formal response from the government as to Bhutto's announcement.

Musharraf is facing surging pressure from opposition groups while contesting for another five-year term, especially since a March attempt to fire the chief justice of the Supreme Court erupted into nationwide street protests and ended with the judge's reinstatement in July.

Vowing to end the rule of General Musharraf, Nawaz Sharif, another exiled former Pakistani leader, was deported to Saudi Arabia on Sept. 10 after a less than five-hour stay in Islamabad's airport.

Sharif, leader of Pakistan Muslim League (Nawaz), another major opposition party, went into a 10-year exile to evade life imprisonment under an arrangement brokered through Saudi Arabia in 2000, one year after General Pervez Musharraf dismissed his government.

Sharif and his PML-N party on Tuesday filed a petition in the Supreme Court against the government for what they called defying an early order of allowing Sharifs' return by the apex court and held Musharraf responsible for "subverting" the law.