The attack near the North Waziristan region highlights concern about the ability of Pakistani troops to stand up to militants who appear to be gaining in strength near the Afghan border.
It was not immediately clear exactly who abducted the soldiers in the village of Buland Khel, said Ghani ur-Rahman, the mayor of nearby Hangu town. He said authorities were contacting tribal elders to seek their help in releasing the men.
Army spokesmen were not immediately available for comment.
Scores of soldiers have been killed or seized in a belt of tribally governed territory along the frontier since the army deployed more troops there in July, prompting fierce fighting with militants and their local supporters.
Authorities on Wednesday sent a delegation of tribal elders to South Waziristan to seek the release of some 260 soldiers kidnapped there Aug. 30.
Local militant leaders are demanding that the government withdraw troops recently deployed in their areas.
Pakistan is a key ally of the United States in its war on terror and says it has deployed about 90,000 troops in the tribal areas to combat militancy and prevent infiltration into neighboring Afghanistan.
The choice of the city of Helsinki is not incidental as the capital of Finland had hosted US-Soviet negotiations on the limitation of nuclear stockpiles in 1969