ISLAMABAD (Reuters) - Gunmen kidnapped the son of a former Pakistani prime minister on Thursday as a letter from the leader of the Pakistani Taliban revealed plans for suicide bomb attacks on election day.

Officials from the Election Commission of Pakistan prepare sacks of stationery materials, before they are transported to polling offices, in the premises of the district city court in Karachi May 8, 2013. REUTERS/Athar Hussain

Pakistani Taliban leader Hakimullah Mehsud, in a message to the group’s spokesman, outlined plans for the attacks, including suicide blasts, in all four of the country’s provinces on polling day on Saturday.

“We don’t accept the system of infidels which is called democracy,” Mehsud said in the letter, dated May 1, and obtained by Reuters on Thursday.

Since April, the al Qaeda-linked Pakistani Taliban have killed more than 100 people in attacks on election candidates and rallies, particularly those of secular-leaning parties, in a bid to undermine elections they regard as un-Islamic.

The polls, already Pakistan’s most violent, will mark the first time a civilian government has completed a full term and handed over to another administration.

The attacks have prevented candidates from the three main parties in the ruling coalition from holding big rallies. Instead, they have relied on door-to-door campaigning or small meetings in homes or on street corners.

Gunmen kidnapped the son of Yusuf Raza Gilani, former prime minister and stalwart of the outgoing Pakistan People’s Party (PPP), as he headed for a small political gathering in the central city of Multan, police said.

Ali Haider Gilani’s secretary and guard were shot dead in the attack.

“If we don’t get my brother by this evening I will not let the elections happen in my area,” said his brother, Musa, in televised comments.

Taliban spokesman Ihsanullah Ihsan denied responsibility in a telephone call to Reuters.

MILITANTS SPARE MAIN OPPOSITION PARTY

The Pakistan Taliban are blamed for many of the suicide bombings across the country, a nuclear-armed strategic ally of the United States.

But they have not attacked the main opposition party led by former Prime Minister Nawaz Sharif, which has courted support from groups accused of supporting militancy.

Sharif, who is seen as favourite to become the next prime minister, says Pakistan should reconsider its support for the U.S. war on Islamist militancy and suggests he would be in favour of negotiations with the Taliban.

Nor have the Taliban attacked former cricketer Imran Khan’s party, which advocates shooting down U.S. drones and withdrawing the Pakistani military from insurgency-infested ethnic Pashtun areas along the Afghan border.

The military said on Thursday it would send tens of thousands of troops to polling stations and counting centres to prevent the Taliban from disrupting the election.

The military has ruled Pakistan for more than half of its 66-year history, either through coups or from behind the scenes.

Army spokesman Major General Asim Bajwa said 300,000 security officials, including 32,000 troops, had been deployed in Punjab, the most populous province. Another 96,000 security forces would be deployed in the northwest.

“Definitely they have reports and obviously they have made a plan to counter that,” newspapers quoted him as saying, referring to security agencies getting threats of violence from the Taliban.

Sharif’s Pakistan Muslim League has capitalised on widespread frustrations with the outgoing government led by the Pakistan People’s Party.