Violence has escalated in the tribal region and fighters have launched attacks almost every day since renouncing a peace accord with the government in July.
In South Waziristan, another tribal area bordering North Waziristan, around 12 men abducted 16 soldiers after they left an army base to go home on leave, an intelligence official said.
The off-duty soldiers were in a van which the kidnappers commandeered at a roadblock near the town of Tank. They were then taken to an unknown destination, the official said.
A man who identified himself as an official from a Taliban movement in Pakistan, claimed responsibility for the kidnapping in a telephone contact with an Al Jazeera correspondent.
Al-Qaida and Taliban-linked Arab, Central Asia and Afghan fighters operate in the two tribal regions which border Afghanistan.
Pakistan has deployed around 90,000 troops to its border regions with Afghanistan to confront the fighters, after increasing pressure from US and Afghan officials to do more to eliminate fighters from its territory.
Suicide bomb threat
In another development on Thursday, in Islamabad, police were looking for a man they suspected of being a suicide bomber after a taxi driver alerted them.
|Security has been tightened in Islamabad after|
two suicide bombings hit the city in July [AFP]
The man, who appeared to be in his 20s and sported a small beard, told the driver of a taxi he had hired that "I and you are going to be martyrs", Zafar Iqbal, Islamabad city police chief, said.
Scared, the taxi driver stopped by a police station, ran in to inform officers about his suspicious passenger, but found that the man had fled, along with the cab, Iqbal said.
The taxi was later found abandoned at a large square near the Parliament building and dozens of police began a search for the man in the neighbourhood, Iqbal said.
Security has tightened in Islamabad since two suicide bombings struck the capital last month in which a total of 29 people were killed