Israeli police say a crash involving a bus and a tractor has killed eight people and wounded at least 20.

Police spokeswoman Luba Samri says it is not immediately clear what caused Tuesday's collision on a highway near the southern town of Lehavim.

Talal al-Krenawi, mayor of the nearby town of Rahat, told Channel 2 TV that the passengers were Bedouin residents of the area returning from a trip to Jerusalem's Al-Aqsa mosque.

Rescue helicopters hovered above the scene, where some 30 ambulances were dispatched to treat the wounded. The windows on the left side of the bus were smashed. A tow truck carried two tractors, and other vehicles were also damaged.

Samri said police closed the road following the crash.