KARACHI (AFP) - A bomb blast targeting an election candidate wounded four people in Pakistan's commercial hub of Karachi as historic elections got underway on Saturday, police told AFP.

"The target of the attack was an ANP (Awami National Party) candidate. At least four people have been injured," senior police officer Tahir Naveed told AFP.

Saturday's election marks the first democratic transition of power in the nuclear-armed state which has been governed by the military for half its history.