RAWALPINDI, Pakistan (AP) - Pakistani opposition leader Nawaz Sharif announced Thursday his party was boycotting next month's elections following the assassination of Benazir Bhutto. He demanded that President Pervez Musharraf resign immediately.
"The holding of fair and free elections is not possible in the presence of Pervez Musharraf. After the killing of Benazir Bhutto, I announce that the Pakistan Muslim League-N will boycott the elections," Sharif told a news conference, referring to his party.
Sharif urged other parties to join the boycott of the Jan. 8 parliamentary elections. A collective response, including by Bhutto's own party could seriously undermine the legitimacy of the vote as Musharraf attempts to engineer a transition to democracy after eight years of military rule.
"I demand that Musharraf should quit immediately," he said. "Musharraf is the cause of all the problems. The federation of Pakistan cannot remain in tact in the presence of President Musharraf."
Sharif, 57, was a longtime rival of Bhutto as the two vied for power in the late 1980s and 1990s. He was ousted in the 1999 coup that brought Musharraf to power.
Sharif said after three days of mourning, he would chalk out a strategy to challenge Musharraf's rule but he rebutted suggestions that he could gain political capital from her demise.
"I think nobody stands to gain and nobody should be looking for any gains," he told the British Broadcasting Corp. "It's a very serious situation for the country today."
As word of Bhutto's death spread throughout a shaken and distraught Pakistan, Sharif rushed to the Rawalpindi hospital where she died and sat silently next to her body.
"Benazir Bhutto was also my sister, and I will be with you to take the revenge for her death," he said afterward, his eyes at times welling up with tears. "Don't feel alone. I am with you. We will take the revenge on the rulers."
Bhutto, like Sharif a two-time former prime minister, was hopeful of winning a third term. Election authorities have disqualified Sharif from contesting a seat because of court convictions.
Bhutto's death will leave Sharif as the most prominent leader of a secular political party in Pakistan.
Bhutto's supporters erupted in anger and grief, attacking police and rioting in several cities. At the hospital where she died, some smashed glass and wailed, chanting slogans against Musharraf.
The gathering unrest stoked fears of mass protests and violence across the nuclear-armed nation, an important U.S. ally in the war on terrorism.
For Sharif, the path forward was far from clear.
"I think we all have to seriously think about how to move ahead because such incidents are something absolutely unusual or unheard of," he told CNN. "We have never been confronted with this kind of a situation in our public life in Pakistan."
Pakistan, however, has seen its share of political violence, and Islamic militants have repeatedly targeted top figures in Musharraf's government. Last weekend, a suicide bomber targeted former Interior Minister Aftab Sherpao inside a mosque, killing 56 other people.
Sharif, a law graduate and the son of a leading industrialist who is considered religiously conservative, rose to prominence under Gen. Zia ul-Haq's military regime in the 1980s, becoming the chief minister of the eastern province of Punjab.
He went on to lead the Pakistan Muslim League and became Bhutto's chief rival in the struggle for power during a turbulent decade of civilian rule.
Sharif was ousted in 1999 by then-army chief Musharraf. Sharif went into exile, living for most of the time in Saudi Arabia, before returning last month to challenge Musharraf once more.