Afghan officials say gunmen traveling in vehicles loaded with explosives killed a policeman and two civilians when police stopped them on a road in the eastern province of Nangarhar.
The provincial police chief said police suspected the gunmen were planning to attack government offices in Batikot district, near the border with Pakistan, on December 31.
A police spokesman said six gunmen opened fire, killing the three people and wounding seven civilians.
He said that some of the gunmen were killed and that police seized the vehicles -- a car and a motorcycle.
Separately, a spokesman for the governor of the central province of Uruzgan said a policeman opened fire on fellow officers as they ate dinner on December 30, killing three and wounding five.
The spokesman said the gunman fled and his motive was not known.
Uruzgan and Nangarhar are hotbeds of militant activity in Afghanistan, where NATO formally ended its combat mission on December 28, after more than 13 years after a U.S.-led coalition invaded to oust the Taliban following the September 11, 2001, terror attacks.