"About their return before elections, no, there is nobody returning before elections," Musharraf, who is both president and the chief of the army, said in an interview with private TV channel Aaj.

Musharraf's statement appeared designed to end speculation that he could strike a deal with Benazir Bhutto to broaden his fragile support base.

Benazir Bhutto, who leads the popular Pakistan People's Party (PPP), went into exile in 1998 over corruption cases pending against her and her husband.

Sharif was sent into exile in December 2000, a year after Musharraf toppled him in a bloodless coup.

The two mainstream politicians, who each ruled Pakistan twice between 1988 and 1999, have repeatedly said they would defy Musharraf and return home to run in elections due later this year or early 2008.

Their hopes have recently received a boost from an ongoing judicial and political crisis sparked by Musharraf's removal of the country's top judge and the resulting violent riots.

Critics say the action against Chief Justice Iftikhar Mohammad Chaudhry was aimed at intimidating the judiciary to aid Musharraf's efforts to retain power.

Benazir Bhutto's party dismissed Musharraf's outburst as nothing but the "dying kicks of a vanishing dictator."

"General Musharraf himself is about to go, his days as the usurper president are over and it is just a matter of time before he has to quit," PPP spokesman Farhatullah Babar told AFP.

He vowed Benazir Bhutto, 54, one of the most colourful and controversial figures in Pakistani life, will return to Pakistan to participate in the elections.

Sharif, who heads his own faction of Pakistan Muslim League, said in an interview this week in Britain's Times newspaper that he also had "every intention" of returning home.

His party leader, Raja Zafarul Haq, said Musharraf had once again shown that he had little respect for fundamental rights.

"Mr Sharif will return to Pakistan this year because he is a citizen of Pakistan," Haq told AFP.

"There is no provision in the constitution which gives power to one man to bar a fellow citizen from entering the country."

Musharraf has said Sharif, 46, could not return for ten years under an agreement brokered by Saudi royal family.

Under the deal, Musharraf ended Sharif's life sentence on tax evasion and treason charges, according to government.

The return to Pakistan of either Benazir Bhutto or Sharif would bring huge crowds of supporters onto the streets and likely provide a focal point for widespread anti-Musharraf sentiment.