More than 30 people, mostly schoolchildren returning from a sports meet, were killed Friday in Morocco when their bus caught fire after a head-on collision with a trailer truck.

The accident in southern Morocco was the deadliest in the North African kingdom since 2012 when a bus plunged into a ravine, killing 42 people.

The early morning collision in the province of Tan-Tan killed at least 33 people, reported MAP news agency quoting local authorities, revising an earlier toll of 31 dead.

They said nine injured people were taken to hospital, but two who were in a serious condition later died.

"A majority of the victims are children aged eight to 14," a regional official from the sports and youth ministry told AFP.

Private media said the bus was transporting the young athletes and their coaches from a competition in Bouznika, a beach resort in the north between the capital Rabat and Casablanca.
Pictures posted on YouTube and on several news websites showed the mangled wreckage of a bus on fire, and witnesses said that many of the victims had been asleep when the collision occurred.

"It is a horrible accident. The toll is huge. The fire broke out when the bus and the truck collided and then it spread," social worker El Hassan Mouline told 2M state broadcaster, speaking from the scene.

He said the victims included children who were taking part in a sporting competition, a local athletics champion and an official from the sports and youth ministry.

"The whole team is lost," Mouline said.

News of the accident triggered panic and parents of children who were on the bus rushed to the hospital in the town of Guelmim, demanding the names of the victims, Medi1TV reported.

But the broadcaster said authorities were still working on identifying the dead.

It also reported that at least four children had survived the tragedy but were being treated at hospital for "third degree burns".

King Mohamed VI sent a message of condolences to the families and said he would pay for the burials as well as cover the cost of hospital fees for the injured.

Media said that Interior Minister Mohamed Hassad would head an official government delegation to Tan-Tan later Friday.

Road accidents are common in Morocco, where officials say about 4,000 people are killed each year -- the equivalent to about 11 every day -- in a country of 34 million inhabitants.

In 2010, Morocco imposed tougher driving laws.

The authorities say that human error, including speeding, are the main cause of most road accidents in the country.

The World Health Organisation says that traffic accidents cost Morocco one billion euros ($1.05 billion) each year, or about two percent of its gross domestic product.