The acting police chief of southern Afghan province has been shot and killed by a fellow officer, about a month after his predecessor was also assassinated.

The death of the second police chief for Uruzgan province to be killed in six weeks appeared to be an insider attack, but it was unclear what motivated the junior police officer to open fire.

"The acting police chief, Gulab Khan, was in a meeting with a friend when his colleague opened fire and killed both of them," provincial governor Amanullah Timori said.

"The policeman is detained and an investigation is ongoing."

The arrested officer was a member of the criminal investigation department in Uruzgan.

Mr Khan had been acting police chief since his powerful predecessor, Matiullah Khan, was killed in a suicide attack while visiting the Afghan capital Kabul in mid-March.

Taliban insurgents claimed responsibility for the attack on Matihullah Khan.