Afghan police say one person has been killed and three others wounded after their vehicle struck a roadside bomb in the capital, Kabul.
A police spokesman said a woman was among those wounded in the blast early on January 13.
The spokesman said the victims were all civilians and their vehicle was destroyed in the blast.
The Taliban claimed responsibility.
In other violence, police said an officer opened fire, killing two colleagues, including a district chief and a police unit commander, late on January 12.
The attack happened in Nowzad district in southern Helmand Province.
The local government said in a statement that three other policemen were wounded.
It said the attacker was shot and later died.
Based on reporting by AP and dpa