At least three supporters of former Pakistan premier Benazir Bhutto [Images] were on Saturday gunned down by unidentified assailants, who attacked her party's office in a village in south-western Balochistan province, the police said.

In a pre-dawn attack, the gunmen opened fire on Bhutto's Pakistan People's Party office in the village, killing three workers and injuring one, the police said.

Officials said the attack could have its origins in tribal rivalries. No further details were immediately available.

Bhutto returned to Pakistan on October 18 from self-imposed exile to lead her party in the general election scheduled for January 8 in the emergency-ruled Pakistan.