Israeli fire near Haifa kills dozens prison guards
Many of the victims were prison guards travelling on a bus which was caught in the inferno in the Carmel Mountains near the city of Haifa.
Thousands of people, some of them prison inmates, have been evacuated from the area, police said.
Scores more have been injured, the ambulance service said. The cause of the blaze was not immediately known.
The Israeli prison service said the bus was carrying guards to help with the evacuation of nearby Damon Prison because of the blaze.
The men had not worked at the prison but had raced to the area from central Israel to assist in the rescue, prison service spokesman Yaron Zamir said.
A fire brigade spokesman told the Jerusalem Post that the blaze had travelled 1,500m (4,920ft) in less than three minutes.
"The bus had no chance. They tried to escape but were burned alive. It was a horrific scene," the spokesman told the newspaper.
No inmates were reported injured.
"This is a disaster of unprecedented proportions," Israel's Prime Minister Benjamin Netanyahu said.
"We are harnessing all the forces of the state to deal with this disaster and rescue those who are injured and to stop the fire," Mr Netanyahu said.
He called on Greece, Italy, Cyprus and Russia to help Israel tackle the fire.
The fire in the northern Carmel region broke out about midday, and hundreds of firefighters were battling the flames on the ground and from the air amid heavy winds.
Emergency crews from across the country tried to reach the scene, weaving through heavy rush hour traffic as night fell.
"We're on a road that takes you down Carmel Mountain and everything is burning on both sides," a paramedic supervisor from the ambulance service, Erez Geller, told the BBC.
"It's dark now and this makes it very complicated with the fire. It's a catastrophe because we have so many fatalities.
"We have had several fires in the last 10 to 12 years but nothing like this," Mr Geller said.
Israeli media said it was the biggest forest fire in the country's history, with 7,000 acres (2,800 hectares) of land destroyed by Thursday evening.
Israel is currently suffering a period of drought with no significant rain since the spring.