The clashes occurred in Shawal tehsil of North Waziristan Agency, army's media wing ISPR said in a statement.
"During an exchange of fire with security forces six terrorists were killed in Shawal today. Lieutenant Colonel Faisal Malik and a soldier also martyred in exchange of fire," the ISPR release added.
The security forces launched grounded operation in Shawal area of North Waziristan last week to clear the remote mountainous region of foreign and local militants.