A suicide car-bomb attack outside a Pakistani election candidate's office killed 37 people and injured 90 others today, the last day of campaigning for a general election meant to complete a transition to civilian rule.
Supporters rally under a billboard of Benazir Bhutto during an election campaign in Peshawar
Police in the south of the country said they had foiled another attack planned for polling day on Monday.
Campaigning for the elections to a new parliament and provincial assemblies has been overshadowed by security fears, especially since former Prime Minister Benazir Bhutto was killed in a gun and suicide bomb attack on December 27th. Opposition politicians have also complained of vote rigging.
The poll could spell trouble for President Pervez Musharraf, a key US ally who stepped down as army chief in November, if voters elect a parliament hostile to him.
Voting was postponed from January 8 following Mrs Bhutto's assassination which raised fears about the nuclear-armed country's stability.
Today's suspected bomb attack in the town of Parachinar, in the Kurram region on the Afghan border, occurred as supporters of a candidate backed by Mrs Bhutto's party were going into his office after a rally, witnesses said. The Interior Ministry said it was a suicide car bomb.
Police in the southern city of Hyderabad said today they had arrested three suspected suicide bombers and seized 10 kilos of explosives and a suicide-bomb jacket.
The violence has unnerved politicians and voters, and turnout on Monday could be low despite the deployment of more than 80,000 troops.
The elections follow months of political turmoil over the increasingly unpopular Mr Musharraf's efforts to stay in power. Opposition parties say his allies have been engaged in widespread pre-poll rigging.
Two-time prime minister Mrs Bhutto had been hoping to win and her Pakistan People's Party is expected to reap a sympathy vote.
But with none of the main parties - the PPP, the Pakistan Muslim League that backs Mr Musharraf, and the party of another former prime minister, Nawaz Sharif - expected to secure a majority, a coalition between two of the three is likely.
Mr Sharif and Mrs Bhutto's widower, Asif Ali Zardari, who is leading her party into the vote, met in Lahore today and warned of trouble if they were robbed of victory.
"If the opposition is deprived of its rightful place in the elections, I think that will be very dangerous. ... It will throw the country into very chaotic situation," Mr Sharif told a news conference.
Mr Zardari told reporters he expected to win but he doubted the vote would be fair. "If they want to rig the election, that we will not take sitting down," he said.
Asked about his talks with Sharif, Zardari said: "We discussed the fact than we can have a broad-based government ... the political forces can take responsibility for the country."
Mr Musharraf rejects complaints of rigging and says procedures have been refined to prevent cheating. He said today he was positive the vote would be fair and peaceful and that he hoped for a stable government.
"We will ensure a successful fight against terrorism and extremism and we will ensure sustaining economic growth," the state news agency reported him as saying.