KARACHI, Pakistan: The suicide attack that killed at least 136 people and shattered the homecoming of former Prime Minister Benazir Bhutto may have been the work of al-Qaida and the Taliban, authorities said on Friday.

More than 250 others were injured in the midnight attack near Benazir Bhutto's vehicle in Karachi, according to Pakistani media reports.

China on Friday "sternly" condemned the attack. "We hope Pakistan will maintain social stability," said Foreign Ministry spokesman Liu Jianchao.