A roadside bomb killed three army personnel in Pakistan's tribal region, the military said Monday.
Two others were injured when the bomb targeted a military convoy that was on patrol in Kurram Agency.
Kurram is one of seven districts in Pakistan's tribal region bordering Afghanistan.
There was no immediate claim of responsibility.
Late last month, a member of Pakistani security was killed and five others were wounded when a car laden with explosives entered a fort in Bara Tehsil in the Khyber district, near the border with Afghanistan.
The blast destroyed five rooms inside Fort Slope, a paramilitary forces camp in the district of Bara in another of the seven semi-autonomous tribal regions of northwest Pakistan, he said.
Militants have a strong presence in Pakistan's volatile tribal region, and paramilitary forces have frequently come under fire.