Officials said Ms Bhutto was unhurt after one of the deadliest blasts in her country's history, having left the truck that had been transporting her through streets crowded with hundreds of thousands of wellwishers.

'Ms Bhutto is safe and she has been taken to her residence,' said Mr Azhar Farooqui, a senior police officer in Karachi.

There was no immediate claim of responsibility. Militants linked to Al-Qaeda, angered by Ms Bhutto's support for the United States war on terrorism, had earlier this week threatened to assassinate her.

Dr Ejaz Ahmed, a police surgeon, said that 84 dead had been brought to three hospitals of the city. A reporter counted 39 bodies in another hospital.

Hospital officials said more than 200 people were wounded.

Photographer Athar Hussain was slightly wounded in the blasts. He described 'a ball of fire' bursting into the air and disappearing after the first blast. Mr Hussain and another photographer on a truck following Ms Bhutto's vehicle then rushed towards the site of the first blast.

'There was another blast and it was more powerful, then I knew it was a bomb attack.' He saw a television cameraman running in front of him killed.

'Bodies were scattered all over and wounded were crying for help. No one went near the bodies out of fear that there could be another blast,' Mr Hussain said.

Rescuers scrambled to drag bodies from the twisted wreckage of blazing vehicles as flames lit up the night sky after two apparent explosions in Pakistan's most violent city.

'The blasts hit two police vehicles which were escorting the truck carrying Ms Bhutto. The target was the truck,' Mr Farooqui said.

Mr Rehman Malik, an aide to Ms Bhutto who was travelling with her on the truck, said the blasts went off while she was resting inside the vehicle.

Ms Bhutto herself seemed to expect some kind of attempt on her life as she set off on the last leg of her journey back to Pakistan on Thursday.

Loved ones
'They might try to assassinate me. I have prepared my family and my loved ones for any possibility,' she told the pan-Arab Asharq al-Awsat newspaper.

President Pervez Musharraf, in a statement issued by the state run news agency, said the attack represented 'a conspiracy against democracy'.

In Washington, the White House condemned the attack.

'The United States condemns the violent attack in Pakistan and mourns the loss of innocent life there,' Mr Gordon Johndroe, White House National Security Council spokesman said.

'Extremists will not be allowed to stop Pakistanis from selecting their representatives through an open and democratic process.'

French President Nicolas Sarkozy urged Pakistani authorities to guarantee the security of politicians in the run up to elections.

Speaking from Dubai, Ms Bhutto's husband Asif Ali Zardari told Aryone World Television: 'I blame government for these blasts. It is the work of the intelligence agencies.'

Intelligence reports suggested at least three jihadi groups linked to Al-Qaeda and the Taleban were plotting suicide attacks, according to a provincial official.

Some 20,000 security personnel had been deployed to provide protection for the returning Ms Bhutto.

'She has an agreement with America. We will carry out attacks on Benazir Bhutto as we did on General Pervez Musharraf,' Haji Omar, a Taleban commander in the Waziristan tribal region on the Afghan border, said by satellite telephone as Ms Bhutto headed for Pakistan.

Ms Bhutto, 54, had returned from self-imposed exile to lead her Pakistan People's Party into national elections meant to return the country to civilian rule. -- REUTERS