ISLAMABAD - President Asif Ali Zardari has voted by post in Pakistan's landmark general election, Presidential Spokesman Farhatullah Babar confirmed on Friday.

He also said that PPP Chairman Bilawal Bhutto Zardari had been denied permission for a postal ballot but did not give an explanation. President Zardari's two daughters, Aseefa and Bakhtawar, also cast their votes by post, the spokesman said, providing no further information. The Taliban have directly threatened Zardari's PPP and its main secular coalition partners which, the party says, dramatically curtailed its ability to campaign in public.

AFP adds: Asked if Bilawal would cast his vote in person on Saturday, senior PPP leader Taj Haider told AFP: "We cannot take this risk because of the bad security situation. Already the son of the former prime minister has been kidnapped."

He praised the election commission for allowing Bilawal's father, President Asif Ali Zardari, a postal ballot, but at the same time expressed sorrow that the same privilege had been denied to Bilawal.

"We cannot take the risk that he physically casts his vote," Haider repeated.

A presidency spokesman confirmed to AFP earlier Friday that Zardari had already voted by post along with his two daughters, Aseefa and Bakhtawar. The precise whereabouts of Bilawal is unclear.

Attacks on politicians and political parties have killed 127 people since mid-April, according to an AFP tally, and the Pakistani Taliban have singled out the PPP and its main secular allies as a particular target.

PPP leader Benazir Bhutto was assassinated in 2007, just before the last elections, leaving her son Bilawal Bhutto Zardari as party chairman, although he is too young to run for parliament until turning 25 in September.