Gunmen have attacked an election rally in Pakistan's southern Punjab province and abducted the son of a former prime minister, intensifying what has already been a violent run-up to Saturday's nationwide elections.

Ali Haider Gilani, the son of ex-premier Yousuf Raza Gilani, is running for a provincial assembly seat in the district of Multan.

He was attending an election event in the town of Multan today - the last day of campaigning across Pakistan - when the gunmen pulled up, started shooting, grabbed and threw him into a vehicle and drove off, witnesses said.A resident of Multan who attended the rally said the attackers first pulled up in a car and motorcycle outside the venue where the younger Gilani was meeting with a few hundred supporters.

When he came out of the building, two gunmen opened fire, killing one of the people in Gilani's entourage."One of the gunmen grabbed Haider who had blood splashed on his trousers," said Shehryar Ali in comments on Pakistani television broadcaster Geo News.

One of Gilani's guards was killed and five people were wounded in the attack , said Punjab government official. It was not immediately known who abducted Gilani or why.

Saturday's election marks a historic milestone for Pakistan as one civilian government completes its term and prepares to hand off to another.

But the race has been marred by a string of violent attacks against candidates and election events. Much of the violence has been at the hands of the Taliban, which has mainly targeted political parties that have supported military operations against the militants in northwestern Pakistan. Gilani is running as a candidate for the Pakistan People's Party, one of the three parties the Taliban has said it is focusing on.

Gilani's father served for roughly four years as prime minister but was forced out of office last summer by the Supreme Court after refusing to pursue a corruption case against President Asif Ali Zardari.