Former Pakistani Prime Minister Benazir Bhutto vowed today to continue campaigning despite a double suicide bomb attack which left more 130 of her supporters dead.
Mrs Bhutto said two bombers struck her homecoming convoy in Karachi last night.
She said her security guards also found another man armed with a pistol and another with what appeared to be a suicide bomb vest.
Speaking just hours after the bloody attack, a defiant Mrs Bhutto declared: "We are prepared to risk our lives, but we are not prepared to surrender."
Mrs Bhutto accused the Pakistani authorities of failing to act on a tip from a "brotherly country" that a suicide bombing was planned.
And she said the bombing was not an attack on her but on democracy and the unity and integrity of Pakistan.
She accused the people behind the attack of wanting to destroy Pakistan and damage Islam and the political rights of all Pakistan's Muslims.
And she insisted that the militants did not enjoy the support of Pakistanis.
The midnight attack in Karachi, which killed up to 136 people, was blamed by the authorities in Pakistan on al Qaida and the Taliban.
The attack - one of the deadliest in Pakistan's history - bore the hallmarks of militants linked to pro-Taliban warlord Baitullah Mehsud and al Qaida, according to Ghulam Muhammad Mohtarem, the top security official in the province.
As forensic experts studied the severed head of one of the bombers to try to determine his identity, Mohtarem suggested the Bhutto camp had got carried away celebrating her return after eight years in exile and had not taken the need for security seriously.
"We were already fearing a strike from Mehsud and his local affiliates and this was conveyed to the People's Party but they got carried away by political exigencies instead of taking our concern seriously," Mohtarem said.
Mrs Bhutto survived unscathed, but the back-to-back explosions that went off near a bullet-proof truck in which she was riding turned her jubilant homecoming parade through the city streets into a scene of blood and carnage, ripping victims apart and hurling a fireball into the sky. The attack shattered the windows of her truck. She appeared dazed afterward and was escorted to her Karachi home.
President General Pervez Musharraf, the nation's leader, phoned Mrs Bhutto today to express his shock and profound grief over the bombing and prayed for the former premier's safety and security, his spokesman said.
"The president and Mrs Bhutto both expressed their unflinching resolve to fight this scourge of extremism and terrorism. They also agreed that there was a need for the entire nation to unite in order to rid the country of this menace of suicide bombings, terrorism and extremism," the spokesman added.
Musharraf resolved to "bring the perpetrators of this heinous crime to justice."
There was no claim of responsibility for the attack, which shed new uncertainty over Bhutto's talks with Musharraf and possible plans for a moderate, pro-US alliance.
Mohtarem said nuts and bolts and steel balls packed around the explosives had made the bombing so deadly. He said it was impossible to prevent more such attacks.
Officials at six hospitals in Karachi reported 136 dead and around 250 wounded.
Karachi police chief Azhar Farooqi said that 113 people died, including 20 policemen, and that 300 people were wounded. It was not immediately possible to reconcile the differing death tolls.
Police collected forensic evidence - picking up pieces of flesh and discarded shoes - from the site of the bombing. The truck was hoisted away using a crane. One side of the truck, including a big portrait of the former premier was splattered with blood and riddled with shrapnel holes.
Interior Minister Aftab Khan Sherpao said 18 police died in the attack, as two police vehicles on the left side of Bhutto's truck bore the brunt of the blast.
He said authorities had done everything possible to protect the huge gathering of Bhutto supporters marking her return, but noted that electronic jammers fitted to the police escort vehicles were ineffective against a manually detonated bomb.
On the eve of Mrs Bhutto's arrival, a provincial government official had cited intelligence reports that three suicide bombers linked to Meshed were in Karachi. The local government had also warned Bhutto could be targeted by Taliban or al Qaida.
Earlier this month, local media reports quoted Mehsud - probably the most prominent leader of Islamic militants destabilising its north-western border regions near Afghanistan - as vowing to greet Bhutto's return to Pakistan with suicide attacks.
Mehsud's spokesman could not be reached for comment, but an alleged associate of the militant commander, Isa Khan, denied Taliban involvement.
"The government's secret agencies are involved in it. Taliban have no part in it," Khan told an AP reporter by phone from the volatile north-western tribal town of Bannu where he is believed to command pro-Taliban militants loyal to Mehsud.
"This was an effort to provoke common people and create hatred against the Taliban. We do not do anything that harm common people."
Karachi, which lies in the far south of Pakistan but has been buffeted by militant attacks in recent years, was quiet today. Schools were closed and traffic was thin, with city residents wary of venturing out.
Unrest broke in two districts but did not appear serious. Hundreds of Bhutto supporters hurled stones at vehicles and shops during a funeral procession for two victims, forcing police to cordon off the area. Elsewhere, Bhutto supporters ordered shops to close and burned tyres in the road.
Mrs Bhutto had flown home on Thursday to lead her Pakistan People's Party in January parliamentary elections, drawing cheers from crowds that police put at 150,000. She has ambitions to win a third term as prime minister.
The throngs reflected her enduring political clout, but she has made enemies of Islamic militants by taking a pro-US line and negotiating a possible alliance with Musharraf.
It remained unclear what impact the attack could have on reconciliation efforts between the two rivals: whether it could stiffen their resolve to fight militancy together or strain already bad relations between Mrs Bhutto and the ruling party supporting Musharraf.
Mrs Bhutto's husband, Asif Ali Zardari, said on Dawn News television that he suspected that "elements sitting within the government" who would lose out if his wife returned to power were involved in the attack.