A Pakistani army officer, two guards and a government official have been abducted in the South Waziristan tribal region of the country, officials said.
No one has claimed responsibility for taking the men from near an army base in the town of Ladha, but officials said on Saturday that tribal leaders were trying to secure their release.
South Waziristan borders Afghanistan, where Pakistani forces have carried out scores of operations against al-Qaeda and Taliban fighters in recent years.
An official, who wished to remain anonymous, identified the abducted officer as Lieutenant Colonel Mohammed Shahid.
Authorities are still trying to free 15 paramilitary soldiers taken hostage earlier this month in region.
Attacks on government and military targets have increased in Pakistan's tribal belt since the storming of the Red Mosque in Islambad in July, in which more than 100 people died.
About 250 fighters and 60 troops have been killed in just over a month in the region, the army said Friday, after intense US pressure to pacify the area.
Major General Waheed Arshad, chief military spokesman, said most of the deaths among the security forces occurred in suicide attacks and roadside bomb explosions targeting their convoys.
Two suicide bombings on Friday, claimed the lives of another six Pakistani soldiers and six rebels, officials said.
The seven semi-autonomous tribal districts have been wracked by violence since a controversial peace deal between the Pakistani government and supporters of the Taliban in the region broke down in mid-July.