DUSHANBE, October 19, Asia-Plus – More than 120 people were killed Thursday night after two bombs exploded among crowds in Karachi celebrating the return of the former Pakistani PM Benazir Bhutto.

Ms Bhutto, who was traveling through crowded streets from the city''s airport to a rally marking her homecoming after eight years in exile, was not hurt.  The truck carrying her had its windows shattered and a door blown off.

The attacks on the motorcade happened despite a heavy security presence following threats from militant groups.

Several Islamist groups, including pro-Taleban militants, had said they would attack Ms Bhutto on her return after she promised to confront those operating in the northern tribal areas bordering Afghanistan.

Her husband, Asif Ali Zardari, said members of the government and intelligence agencies who were going to lose power were behind the attack.

Ms Bhutto earlier warned that if targeted she would hold what she described as hidden authorities within the government as partly responsible.  Ms Bhutto wants to contest parliamentary elections due to be held in January and she had been negotiating with President Pervez Musharraf over a possible power-sharing agreement.

Gen Musharraf said the attack was a "conspiracy against democracy".

"The president appealed to the nation and especially the people of Karachi to exercise patience and calm in this hour," said a statement by his office.

The White House also condemned the blasts.  "Extremists will not be allowed to stop Pakistanis from selecting their representatives through an open and democratic process," said National Security Council spokesman Gordon Johndroe.

Most of the dead were members of Ms Bhutto’s Pakistan People’s Party (PPP), although police vehicles took the main force of the blasts and more than 20 police officers are thought to have died.  One cameraman for a local TV station was also killed.

The chief of police in Karachi, Azhar Farooqi, said a preliminary investigation suggested the second blast had been caused by a suicide bomber.  "The first blast was probably a hand grenade and it did not cause much damage," he told the BBC.

Ms Bhutto flew in from Dubai earlier on Thursday, accompanied by about 100 PPP members.  At least 200,000 people turned out to greet her in what correspondents described as a carnival atmosphere, but the crowds slowed the progress of her convoy.  Ms Bhutto had been planning to make a speech at the tomb of Pakistan''s founding father, Mohammed Ali Jinnah.

Ms Bhutto left the country shortly before Gen Musharraf seized power in a coup, but returned under a power-sharing deal that could see her becoming prime minister again.

The US has backed the deal, amid concerns about the military''s inability to defeat Islamist militants and Gen Musharraf''s rising unpopularity.