Officials in Pakistan say gunmen killed two people Friday during an assault on a NATO supply truck in Pakistan's Khyber tribal region.
The unidentified attackers torched the vehicle after killing the driver and another worker.
Pakistan's Dawn News agency reports truck drivers staged a protest at the site of the attack and suspended work.
The assault was the latest in a spate of attacks on the supply line used to carry resources through Pakistan to NATO forces fighting in Afghanistan.
The assaults intensified when Pakistan temporarily shut a key border crossing after a NATO helicopter strike killed two Pakistani border guards.
Elsewhere in the northwest, security officials say a suspected U.S. drone missile strike in North Waziristan killed three militants. They say Friday's strike targeted a vehicle in the village of Machi Khel - an area said to be home to Taliban militants and other insurgents.
There has been a sharp increase in unmanned missile strikes in the tribal region, with 21 attacks in September alone.
Pakistan has protested the strikes as a violation of its sovereignty. The United States does not officially acknowledge the attacks.
In a separate attack Friday, officials say an assailant threw a grenade near a local government office in the northwestern city of Peshawar, wounding at least two children.
Some information for this report was provided by AP, AFP and Reuters.