The death toll from the suicide bombing has risen to at least 133, with more than 400 injured, the deadliest suicide attack in Pakistan's history, turning a welcome home parade into a scene of carnage and chaos.

Police recovered a severed head and mutilated corpse of a man they say was a suicide bomber. DNA tests are being carried out to establish an identity.

President Pervez Musharraf has given the security agencies 48 hours to report back on their investigation.

Hospitals treating hundreds of injured survivors have issued an urgent appeal for blood donors.

Efforts to identify victims in mortuaries have been stepped up to ensure burials can take place before sunset, in accordance with Muslim traditions.

Police have discounted initial reports the blast came from inside a police escort vehicle. Benazir Bhutto escaped unhurt and is now safely behind a heavily guarded family compound.

Ms Bhutto's party says she will stay in Pakistan to contest next year's election despite the attack.

A senator with the Pakistan People's Party says Ms Bhutto is determined to continue her fight for democracy and will not change her plans.

Her party has declared three days of mourning and some supporters have begun burning tyres and blocking streets in protest at the attacks. © 2007 Australian Broadcasting Corporation