The Pakistani army has widened its offensive against insurgents following battles in the Swat Valley in the north of the country.
Troops are reported to be pouring into South Waziristan, a key region near the border with Afghanistan.
The fighting has created a huge refugee crisis with over two million people fleeing their homes.
The offensive is part of a campaign by the US and its allies to crush insurgencies in both countries.
Reports from the area say that Pakistani troops entered key towns after fighters left.
Last month 12 British soldiers were killed in Afghanistan, raising the number of British troops who have died since the invasion in 2001 to 156.