Pakistani military officials say eight soldiers have been killed in an operation against militants in the country's Khyber tribal region.
The clash Wednesday also left 21 militants dead and several wounded in the Spin Qamar area.
Pakistan has been battling Islamist groups in its semiautonomous tribal belt since 2004.
Also Wednesday, the military declared its four-month-old push against militants in North Waziristan a success.
Officials said troops have killed 1,100 militants in North Waziristan. The casualty figures could not be independently confirmed, because journalists are not allowed to report from the tribal regions.