Taliban militants have killed at least 13 people and are holding more than 30 hostage after an ambush on a highway in northern Afghanistan.

Afghan officials said four buses were stopped by militants early on May 31 in the Aliabad district of Kunduz Province.

The militants took 185 passengers hostage initially and killed 13 of them, all civilians, but freed the rest, provincial press officer Hejratullah Akabari told RFE/RL's Radio Free Afghanistan.

Locals say that 18 hostages were killed brutally by Taliban militants and the bodies of five them thrown in a river.

The Taliban claimed responsibility for the attack, saying they were targeting security officials.

Taliban forces regularly stop passenger vehicles to search for members of the Afghan government, security forces, and international organizations, and the number of such incidents appears to be growing.

Kunduz is one of the most embattled provinces in northern Afghanistan. Kunduz city, the capital of the province, briefly fell to the Taliban last year.

With reporting by AFP and dpa