He said a convoy of troops had retaliated after coming under attack by insurgents in Miran Shah, in the North Waziristan tribal area. Six soldiers and 15 militants were subsequently killed in the shootout. A further 20 soldiers were injured.
Waheed said troops were currently searching for the remaining militants.
The spokesman had earlier claimed that at least 230 Islamic insurgents were killed in northwest Pakistan last month, mostly in an ongoing army operation in the Swat Valley, near the country's border with Afghanistan. The area has seen an upturn in Islamic militant activity recently
He also said most of the valley had now been cleared of extremists, and that the military had retaken control of many areas.
The official also commented that foreign Islamic militants were among those killed, and that a large amount of weapons and ammunition had been seized.
The operation in the Swat Valley started in October, when the Pakistani authorities deployed 2,500 troops in order to stabilize the situation in the area.