Islamabad, Pakistan (CNN) -- The Pakistani military killed 20 militants during military operations in northwest Pakistan late Sunday night and into Monday morning, a senior military official told CNN.
The official, who asked not to be named because he is not authorized to speak to the media, said troops used tanks and artillery to target Taliban hideouts in the village of Shahukhel in Pakistan's Northwest Frontier Province.
Troops are facing heavy resistance from the militants, who are using rockets and grenades to fight back near Pakistan's border with Afghanistan, the official said.
There has been an increase in militant activity in the northern districts of the tribal region because militants have fled to those areas from South Waziristan, where the army continues its offensive against the Taliban, Pakistan's top military spokesman, Maj. Gen. Athar Abbas told CNN Sunday.
Journalist Nasir Habib contributed to this report.