Pakistan on Friday arrested 22 tribesman it holds collectively responsible for the kidnapping of eight government officials in South Waziristan.
Pakistan's tribal areas, which include South Waziristan, are governed by colonial-era legislation under which relatives, tribesmen and neighbours of suspects can be arrested and detained for years without trial for a crime committed by another.
Eight officials from the Fata Development Authority (FDA) which operates in federally administered tribal areas were abducted on Thursday.
"We have arrested 22 tribesmen to put pressure for the release of the eight FDA officials as the kidnapping took place in their area and it is their collective responsibility to help authorities in the recovery," Masood Khan, a political officer said.
No group has claimed responsibility for the abduction of the officials yet.
The South Waziristan enclave on the Afghan border forms one-fifth of the Federally Administered Tribal Areas and is governed under a system inherited from Britain.
Government-appointed political agents rule through the Pashtun tribes and collect and distribute revenue with little oversight. The people have limited rights.
While the Pakistani Army backed the Taliban in Afghanistan in the 1990s and has supported militants fighting Indian rule in the disputed Kashmir region, it found itself under attack in South Waziristan.
Decades of resentment felt by the population and a US bombing campaign on the Afghan border following the September 11, 2001, attacks on the United States spawned a generation of Pakistani militants who used South Waziristan to launch assaults against the state and US-led forces in Afghanistan.
In 2009, Pakistan's army ordered the biggest offensive yet, pouring 40,000 troops into South Waziristan in a bid to tip the balance of the fighting there. The offensive displaced almost half a million people as homes, schools and hospitals were turned into hideouts by militants and civic amenities were destroyed.