Former Pakistani Prime Minister Benazir Bhutto said yesterday she would carry on her struggle for democracy, despite an attack on her motorcade that killed 133 people as she returned home after eight years of exile.

"We are prepared to risk our lives. We're prepared to risk our liberty. But we're not prepared to surrender this great nation to militants," Ms Bhutto, wearing a black armband, told a news conference at the home of her parents-in-laws in Karachi.

"They're killing our armed forces in the tribal areas of Pakistan, they're knocking on the doors of the Frontier Province," Ms Bhutto said, referring to a deepening conflict near the border with Afghanistan where Taliban and al Qaeda fighters are based.

The 54-year-old former prime minister returned on Thursday to lead her Pakistan People's Party into national elections due in January that are meant to mark a transition from military to civilian led democracy.

"The attack was on what I represent. The attack was on democracy and very unity and integrity of Pakistan," Ms Bhutto said.

"I knew the attack could be carried out but I was prepared to take this risk for my people and my land."

Ms Bhutto had always vowed to return to end military rule in Pakistan, but she has come back as a potential ally for President Pervez Musharraf, the general who seized power in a 1999 coup. President Musharraf has promised to be sworn in as civilian president if the Supreme Court dismisses challenges and his October 6 re-election by parliament is ratified, and there is speculation that he could share power with Ms Bhutto after the January election.

The attack shortly after midnight was perilously close to the armour-plated truck transporting Ms Bhutto to a rally planned near the tomb of Pakistan's founding father, Mohammad Ali Jinnah.

She escaped unhurt, but the bodies and limbs of supporters and members of her police security escort were scattered all around.

Ms Bhutto described hearing the blasts while sat inside the truck working on a speech she was to deliver to a rally.

"We know shots were fired and these were fired towards the truck."

She said shots were fired to stop the truck or to kill bystanders, and that a man armed with a pistol had been caught.

"We don't know whether it was deliberate attempt to stop the truck by firing at the driver," she said.

She also questioned why the street lighting was not working on the stretch of road where the attack happened.

Ms Bhutto said she expected more attempts on her life, and feared an assassin could be planted in the police, and said she had written to President Musharraf naming three people who represented the forces of militancy.