A jeep crammed with asylum-seekers has crashed on a northern Greek road, killing six people, including three children, and severely injuring another four adults.

Police said the vehicle was carrying 16 men, women and children when it veered off the road and crashed into rocks near the town of Kavala.

Three of the survivors are being treated for severe head injuries and another is being operated on for bone fractures, while the remaining six were less seriously hurt.

The driver, who was a member of a migrant-smuggling gang paid to ferry the asylum-seekers west, was among the dead. Authorities said the migrants were Syrian and Iraqi nationals.

Police said the cause of the crash was unclear, but the vehicle was not being pursued by patrol cars at the time of the accident.

Authorities were notified by motorists who saw the wrecked jeep by the roadside.

Police said the vehicle had come from the north-eastern Evros region, on the border with Turkey, which is a major crossing point for Middle Eastern, Asian and African migrants and refugees seeking a better life in Europe.

Accidents are frequent, as smuggling gangs try to drive asylum-seekers in desperately overcrowded vehicles as quickly as possible to Thessaloniki, sometimes chased by police.