Ali Haider Gilani, second from left, an election candidate and the son of former Prime Minister Yusuf Raza Gilani, talks with supporters prior to his abduction by unknown gunmen. (STR/EPA)

Gunmen kidnapped the son of a former Pakistani prime minister Thursday at a campaign rally in southern Punjab province as violence continued to rise ahead of Saturday’s national election , which some call the bloodiest in the country’s history.

Hours after his youngest son, Ali Haider Gilani, was kidnapped and two others killed in the attack, ex-premier Yousuf Raza Gilani urged supporters of their Pakistan People’s Party to keep campaigning. The young Gilani is a candidate for the provincial assembly in the Multan district, where the attack occurred and where two of his brothers are running for seats in Parliament.

Their father, who served as prime minister for more than four years until he was forced to step down by the Supreme Court in a contempt case last year, accused the temporary caretaker government of not providing sufficient security for candidates.

Islamist militants have waged bomb and gun attacks for the past month against the liberal People’s Party and two secular coalition partners in the outgoing government.

The moderate forces in the country were not being provided with “the favorable environment to campaign and take part in elections,” Yousuf Raza Gilani told reporters at his home in the central city of Multan, adding that his son’s secretary and guard died in the attack.

He said he did not know who carried out the kidnapping.The Pakistani Taliban, which has asserted responsibility for previous attacks and has threatened to kill voters at the polls, said it was not behind the Multan incident, the Reuters news agency reported.

The gunmen grabbed Ali Haider Gilani after he left a building to meet with a few hundred supporters, according to local television newscasts.

Because of the recent attacks, which have killed more than 110 people since April, the People’s Party, the pro-U.S. Awami National Party and the Karachi-based Muttahida Qaumi Movement have been constrained in their campaigning.

Rather than holding large rallies, they have relied mostly on advertising, door-to-door politicking and small meetings. They also have demanded more security, but there has been no response from the caretaker government.

Also Thursday, a bomb exploded at an election office of a leading conservative religious party, Jamiat Ulema-e-Islam, in the militant stronghold of Mir Ali in the North Waziristan tribal area, officials told the Associated Press. One person was killed and six wounded, the AP reported.

On Monday and Tuesday, rallies for candidates under the banner of Jamiat Ulema-e-Islam were bombed, killing more than 30 people.

The vote is historic because it is expected to bring a transition of power from an elected government, which served an unprecedented full term, to another elected government. The military has staged coups three times and has been in power for more than half of Pakistan’s 65-year-old history.