* Most of the dead believed to be prison guard cadets
* Turkey, Greece and Cyprus among countries sending aid
* Kibbutz farm destroyed, thousands evacuated
(Recasts with fresh details, changes byline, pvs HAIFA)
By Douglas Hamilton
TIRAT CARMEL, Israel, Dec 2 (Reuters) - A huge forest fire killed about 40 people in Israel on Thursday, including young prison guard cadets trapped in a bus while heading to help inmates flee the flames, officials said.
More than 12,000 people were evacuated from towns and villages as the fires, said to be the worst in the country's history, blazed out of control.
A collective farm in the forest, Kibbutz Beit Oren, was razed. Television showed a gutted bus and car which had been carrying prison guards and rescuers when they were engulfed by the flames.
Israeli Prime Minister Benjamin Netanyahu said on a visit to the scene by helicopter Israel had suffered a "disaster on a scale we have never seen before".
"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," he added.
Netanyahu called an extraordinary session of his security cabinet before the weekend to decide further steps.
Turkey, despite its strained ties with Israel, was one of eight countries sending aircraft and flame retardants to help fight the flames, Israeli officials said.
Tirat Carmel, a town near Haifa, was the latest of more than a dozen towns and cities evacuated. Police officers blared orders through megaphones for residents to leave as smoke engulfed the town and spread across the hillsides.
"ENORMOUS DISASTER"
"There are a lot of casualties. We are talking of about 40 people," said Police Minister Yitzhak Aharonovitch, adding that a handful of people were missing in addition to those known to have been killed.
"What is happening here behind us is there's a fire that is blazing out of control, moving toward the west ... It is an enormous disaster," Aharonovitch added.
Micky Rosenfeld, a spokesman for national police, said two of those missing were police officers and that a senior commander of the Haifa force had been critically injured.
Paramedics said they had found 36 bodies.
Israeli firefighters said it was the biggest forest fire in the country's history, with some 7,000 acres (2,800 hectares) of land destroyed.
Some 500 inmates from the local Damon prison were moved to safety in the early afternoon as the blaze spread.
Benny Kaniak, head of Israel's Prison Services, said the prison guards who were killed were cadets who had been on the way to help evacuate the prison.
The fire started around midday, possibly in an illegal dumping ground in the Carmel Hills south of Haifa, Israeli media said.
Israel has experienced unseasonably hot weather for months and it was the driest November in 60 years, meaning the flames were able to spread quickly through the tinder-dry countryside. (Additional reporting by Allyn Fisher-Ilan in Jerusalem; editing by Andrew Roche) (allyn.fisher.thomsonreuters.com; +972-2-6322202; Reuters Messaging:allyn.fisher.thomsonreuters.com@thomsonreuters.net))
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