Local officials claim the troops were taken hostage by the Taliban when armed men ambushed their convoy.
The soldiers lost contact with army headquarters, sparking fears they had been abducted, officials said.
Rahman said reports have suggested there did not seem to be an exchange of fire.
He said: "It seems they [the Taliban] were very well organised.
"The Taliban and the Pakistani soliders both see each other as Pakistani brothers. It seems they would have wanted to avoid a firefight. But none of this can be confirmed."
He said tribal elders were acting as go-betweens, and the soldiers had been separated and taken into nearby hills, according to Taliban sources.
One Pakistani security offical said: "There are around 150 soldiers and they are trapped in a situation where it will be risky for them to get out without settlement of a dispute between local militants and tribal people."
On Friday, Major General Waheed Arshad, Pakistan's senior military spokesman, announced that around 100 troops were stranded in the region amid fighting between soldiers and Taliban fighters.
But he dismissed reports that the troops had been kidnapped by the Taliban.
He said a group of fighters wanted to take the soldiers hostage but tribal people were opposing them.
Concern for the troops comes after Taliban members in South Waziristan on Tuesday released 19 Pakistani soldiers who were abducted in August.
One of those soldiers was beheaded on video by a teenage boy on August 14.
The border area is a known hub of Taliban and al-Qaeda-linked fighters engaged in a bloody confrontation with tens of thousands of troops deployed in the region since 2002.
Pervez Musharraf, Pakistan's president, has been under pressure from Washington to crack down on militancy in the restive frontier region, where US officials say al-Qaeda's leadership has regrouped.