The incident happened in the Waziristan district of the province where the two sides engaged in a gun battle, Xinhua news agency reported quoting the Inter-Services Public Relations (ISPR), the military's media wing.
A clearance operation is being conducted to eliminate any other terrorists found in the area.
The country's Prime Minister Shehbaz Sharif lauded the military for eliminating the terrorists and paid tribute to the killed troops for their valor.
Earlier on September 20, six troops and 12 terrorists were killed in two separate clashes between the militants and security forces in Pakistan's northwest Khyber Pakhtunkhwa province.
The terrorists attacked a check post of security forces in the Waziristan district of the province, triggering an exchange of fire and resulting in the killing of seven militants.