“Unfortunately as a result of this blast, 12 women, four children and one man have been killed and five children, one man and one woman have been wounded,” Herat province police spokesman Abdul Rauf Ahmadi told AFP.

Sher Agha, the police chief of Herat's Obe district, said that the three-wheel vehicle struck a roadside mine planted by the Taliban as it travelled from Obe district centre to a nearby village.

Also on Tuesday, an Afghan soldier shot dead a Slovakian soldier, officials said, in the latest “insider attack” to shake efforts by the Nato coalition and the Afghan army to work together to defeat the Taliban insurgency.

The shooting occurred outside Kandahar airfield, one of the biggest military bases in southern Afghanistan and a hotbed of the 12-year conflict with the Islamist rebels, a senior Afghan officer told AFP.

Nato's International Security Assistance Force (Isaf) said in a statement that a “service member died when an individual wearing an Afghan National Security Force uniform fired his weapon at Isaf individuals”.

In line with Nato policy, the statement said the coalition would defer casualty identification procedures to the victim's national authorities.

Western officials in Kabul confirmed that the victim was Slovakian.