At least 42 people died and more than 20 others have been injured when a bus plunged into a ravine in southern Morocco, officials say.

The bus, which had been travelling between the cities of Marrakesh and Zagora, crashed near the town of Zerkten in Haouz province, local officials said.

Most of the passengers are believed to be Moroccan. It is not clear if any foreigners are among the casualties.

At least 42 people died and more than 20 others have been injured when a bus plunged into a ravine in southern Morocco

The accident happened in the early hours of Tuesday, the official news agency Map reported. The cause is not yet known.

At least 24 people were said to be injured, 21 of whom were taken to a hospital in Marrakesh and the other three to a hospital in the nearby city of Ouarzazate.

In July, two separate bus crashes in Morocco killed 26 people.

More than 4,000 people died in road accidents in Morocco last year, according to the transport ministry – an increase of 11.6% on the previous year.