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A homicide bomber rammed a car laden with explosives into the election office of an independent candidate in northwest Pakistan Saturday, killing 37 people days before a crucial parliamentary vote, government officials said.

More than 90 people were wounded. Bodies were seen lying in pools of blood following the blast in Parachinar, a volatile tribal area bordering Afghanistan, one witness said.

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Most of the victims appeared to be members of the opposition Pakistan People's Party, formerly headed by the slain Benazir Bhutto. They had gathered at the candidate's home following a campaign rally, said Mushtaq Hussain, an administrative official in the Kurram area.

He said a homicide bomber apparently "rammed his explosive-laden car into the election office."

Interior Ministry spokesman Javed Iqbal Cheema said 37 people were killed and more than 90 wounded when a homicide bomber drove into a crowd as they were preparing to eat.

The injured poured into a nearby hospital, many in critical condition with severe burn wounds, said Raza Hussain, one of the doctors.

"Several of our party members are lying in a pool of blood," said Zafar Ali, a party supporter at the scene.

The attack came two days before parliamentary elections considered crucial to restoring democracy in Pakistan after eight years of military rule under President Pervez Musharraf.

Recent opinion polls show the opposition poised for a landslide victory amid disenchantment Musharraf's rule.

Interior Minister Hamid Nawaz would not speculate on who may have been responsible, saying "let us first look into it." But Monday's elections are taking place against a backdrop of rising Islamic militancy throughout Pakistan, and many candidates have been discouraged from holding large rallies. Security fears are highest in lawless tribal areas along the Afghan border.

The Dec. 27 assassination of opposition leader Bhutto and a string of homicide bombings — some targeting campaign rallies — have been blamed on Al Qaeda- or Taliban-linked militants.

Earlier on Saturday, more than a dozen bombs heavily damaged a partially constructed jail that was to be used for voting in Khar, the main town in the Bajur area along the border with Afghanistan, said Mowaz Khan, tribal police officer Mowaz Khan. He said the bombs were detonated by remote control. Nobody was hurt.

In the southwestern city of Quetta, hundreds of police surrounded and then clashed with more than 1,500 supporters of a coalition of anti-Musharraf parties boycotting the vote, leaving seven people injured.

The demonstrators threw rocks at police, who responded with tear gas before arresting 50 activists for the violence, police officer Raja Mohammed Ishtiaq said. A truck and three motorcycles were burned in the melee, and the street littered with party flags and shoes.

The government has deployed 81,000 soldiers to back up 392,000 police assigned to protect voters, said military spokesman Maj. Gen. Athar Abbas.

Musharraf said Saturday he was confident the elections would be free and fair and, hopefully, without violence.

"We will have a stable, democratically elected government and with the stable, democratically elected government we will ensure a successful fight against terrorism and extremism," he said in a speech to diplomats and senior government officials that ran on state-run Pakistan Television.

Although Musharraf is not up for re-election, he could face impeachment if the opposition wins a two-thirds majority in the legislature.

Opposition politicians fear the results will be manipulated in hopes of assuring the ruling party enough seats to block any impeachment.

Kanwar Dilshad, the No. 2 official in Pakistan's Election Commission, insisted there would be no rigging.

"We are neutral. A level playing field has been provided to all the contesting candidates, and we are doing our job to ensure free, fair, transparent and peaceful elections," Dilshad told The Associated Press.

Last week, New York-based Human Rights Watch questioned the election commission's impartiality, saying it has ignored complaints of harassment against opposition candidates.

On Friday, Sen. Joseph Biden, a Delaware Democrat who heads the Senate Foreign Relations Committee, said the United States should consider cutting off military aid to Pakistan if the elections are rigged