At least 23 people have been killed in western Afghanistan after a fuel tanker collided with a van, official have said, in the latest accident in a country with poorly maintained roads and often reckless driving.

The crash took place on Sunday morning on the main highway between the city of Herat and the Iranian border, said Raouf Ahmadi, a spokesman for the provincial police chief in the western Herat province.

He said the four people were injured in the accident.

Authorities do not know what caused the accident, but Ahmadi said initial reports indicated that ''both drivers' carelessness'' was to blame.

Afghanistan has frequent traffic accidents often caused by bad roads and poor driving.

On August 17, a truck loaded with people and animals crashed in a mountainous area of northwestern Afghanistan, killing 32 people.