Israeli medical officials say at least 44 people have been killed in a stampede at an overcrowded Jewish religious festival in northern Israel.

Tens of thousands of people, mostly ultra-Orthodox Jews, had attended the celebrations.

Witnesses say the stampede began when large numbers of people trying to exit the site passed through a narrow tunnel-like passage.

People began falling on top of each other near the end of the walkway, as they descended slippery metal stairs.

About 150 people were injured in what was described as one of the country's deadliest civilian disasters.