Pakistani soldiers are searching for about 20 al-Qaida prisoners - mostly Arabs from Yemen - who escaped during a gunbattle Wednesday while being transported to a jail.
The army sealed off the rugged area of the semi-autonomous Pashtun tribal region of northern Pakistan along the border with Afghanistan.
Six Pakistani soldiers and seven prisoners were killed during the gunbattle.
The escapees are among 156 al-Qaida fighters captured by the Pakistani army as they fled Afghanistan's Tora Bora region.
Meanwhile, U-S forces backed by helicopters and high-flying reconnaissance planes are continuing to search the Tora Bora cave and tunnel complex for surviving al-Qaida fighters.
And in New York, the United Nations Security Council is preparing to authorize an international peace keeping force for Afghanistan.
The council is expected to vote today (Thursday) on a draft resolution that gives the multinational force a six-month mandate and the right to use force.
The first batch of peacekeepers is expected in Kabul by Saturday, when the new interim Afghan government takes office.
Britain is to lead the peacekeeping force of about three-thousand troops from a number of countries.