A Pakistani soldier was killed and three others wounded when their vehicle hit an improvised explosive device in the northwestern South Waziristan tribal district.
District police officer Shaukat Ali told RFE/RL that the soldiers were on routine patrol when the attack occurred in the Makeen area on September 14.
The military launched a search operation following the incident, but no arrests have been made so far, said Ali.
No group has immediately claimed responsibility.
In early September, at least four Pakistani soldiers were killed and four others wounded in two different attacks in South Waziristan that were claimed by the Tehrik-e Taliban Pakistan, also known as the Pakistani Taliban.
The latest incident comes a day after the Pakistani military said it had killed a “terrorist” commander and three other militants near the boundaries of the North and South Waziristan districts.
The Pakistani military has claimed it cleared the two districts, located in Khyber Pakhtunkhwa Province, of the TTP and other militant groups following a major offensive that was launched in 2014.
However, the region has been the scene of an increasing number of attacks on security forces and the targeted killing of civilians.