A remote-controlled bomb ripped through a police pick-up truck in northern Afghanistan on Thursday, killing a district police chief and his three bodyguards.

A remote-controlled bomb ripped through a police pick-up truck in northern Afghanistan on Thursday, killing a district police chief and his three bodyguards, officials said.

Police are increasingly targeted by Taliban insurgents as Afghan security forces take greater responsibility for security before NATO troops withdraw next year.

The attack came as the men were travelling from Kishindih district of Balkh province to the capital Mazar-i-Sharif, deputy provincial police chief Abdul Razaq Qaderi told Agence France Presse.

Three others were wounded in the attack, Balkh provincial governor's spokesman Farhad Munir said.

Roadside bombs, either remotely-controlled or weight-detonated, are most common weapons used by the Taliban who have waged an 11-year war against the Western-backed government of President Hamid Karzai.

Suicide attacks are also frequently used, and 10 policemen were killed in the northeast city of Kunduz on January 26 when a bomber blew himself up.