"There are suspicions that their vehicles were detained after they came under attack.
"There are fears that they may have been kidnapped by the militant groups, but the militant groups have not yet confirmed that they had done so."
Early reports in the Pakistani media suggested that up to 400 students and teachers from the college might have abducted.
The college is an army-run educational institution for civilians, with students that are reportedly aged between 15 and 25 years and were not training for the army, but were following a secular curriculum.
Javed Alam, a vice-principal of the college, said the convoy was carrying that more than 300 students and about 30 staff members and employees of the college when they were stopped.
"Militants started firing in the air to stop the vehicles and then they forcibly drove them to unknown place" he told a local television channel.
Negotiations were reportedly under way to secure the release of any students held by the armed men.
"We are negotiating with the militants through tribal elders," Iqbal Marwat, the police chief in Bannu, told the AFP news agency. "We hope they will be freed unharmed."
There are conflicting reports about whether the school had closed for the summer holidays or whether there were concerns that a military offensive could begin in neighbouring South Waziristan.
The incident came as the Pakistani military continued to battle Taliban fighters in the Swat valley in North West Frontier Province (NWFP).
Officials lifted the curfews in the towns of Bahrain, Madyan, Fatehpur, Khwazakhela, Matta and Alpurai and in the district of Shangla in the Swat valley on Monday.
The move allowed thousands of people trapped amid the army's campaign against Taliban fighters to search for food and supplies.
The military has said it is pushing the Taliban back after it regained control of Mingora, the main city in Swat, following weeks of fighting.
However, there are fears that military successes will lead to retaliatory Taliban attacks in other areas.
At least two people were killed and 18 others wounded when a blast struck a bus stop in Kohat on Monday.
Kohat is an important garrison town in NWFP.
Ehsanullah Khan, a senior police official, said that the explosive device was hidden in a sack and confirmed it was detonated by remote control.
Pakistan has stepped up security in its cities following recent suicide bombings away from Swat, including one in Lahore, in the eastern province of Punjab, that killed about 30 people.
Analysts say that the authorities must rapidly restore basic services to stop the Taliban from exploiting frustrations and poverty to remount its campaign.
Sebastian Brack, a spokesman for the International Committee of the Red Cross, told Al Jazeera that those who remained in the valley, as well as the hundreds of thousands of refugees, faced numerous problems.
"There are huge problems in terms of basic services that need to be provided - electricity, water, phone lines, the re-establishment of family links," he said.
"The second level of the humanitarian problem is all those people who found refuge in host families, which are fairly close to the area where the fighting is taking place but which are not receiving the bulk of the humanitarian relief effort.
"That effort is being concentrated further south at the IDP [internally displaced persons] camps."
The Pakistani army launched its offensive against Taliban fighters in Swat and surrounding districts a month ago after they violated the terms of a ceasefire.