The inferno, which also displaced thousands, is still raging through forests in northern Israel and on the outskirts of the country's third largest city, Haifa. An unprecedented convoy of international assistance poured in after Israel issued a rare cry for help.
Israeli officials said some 100 firefighters from Bulgaria have arrived as well as forces from Jordan and Greece. Fire extinguishing planes were on their way from Britain and Cyprus as well as aid from the United States, Russia, Egypt, Spain, Azerbaijan, Romania and Turkey - which put aside recent tensions to lend a hand.
Foreign Minister Avigdor Lieberman said all international aid was expected to arrive by Friday afternoon. In an interview with Israel Radio, he expressed hope that the fire could be suppressed by Saturday night.
Police spokesman Micky Rosenfeld said the death toll has risen to 41, all from a bus of Israeli prison guards that caught ablaze as it headed to rescue Palestinian inmates at a nearby prison threatened by the massive blaze. Rosenfeld said 16 people remained hospitalized, including the police chief of Haifa who was in critical condition. Three others were seriously wounded.
Some 30,000 people were evacuated from their homes and more than 10,000 acres of the Carmel forest in Israel's Galilee has been burned since the fire started Thursday, he said.
The Israeli Cabinet was set to convene in the morning hours for an emergency meeting about the disaster. Prime Minister Benjamin Netanyahu called the fire a "disaster of unprecedented proportions.'' He was set to inspect firefighting efforts after the meeting.
Israeli rabbis issued a special prayer for the victims of the fire.
Police also evacuated a university, three prisons and a hospital.
Investigators speculated that the fire could have been sparked accidentally, or it might have been deliberately set. But they largely ruled out any sort of attack by a Palestinian group.
The fire broke out around midday and quickly spread, fanned by unusually hot and dry conditions. Israel experienced an exceptionally warm summer and has had little rain during the normally wet autumn.
Flames ripped through the Carmel forest in Israel's Galilee region, eventually reaching the coastal city of Haifa after jumping from place to place in the forest.
As guards raced toward the nearby Damon prison, a lone tree fell across the road, blocking their path. With no way out, many of them were burned alive inside the vehicle. Others perished while trying to flee the flames fed by brush left tinder-dry by lack of rain.
Israel's call was a rare appeal for international assistance. The Jewish state is better known for sending its own rescue teams and medical personnel to other countries to help in their disaster-relief efforts.
Flames heavily damaged one of Israel's few large forests, made up of natural growth and planted areas, a favourite spot for camping, hiking and picnics. The woods provided a refuge for dozens of species of wildlife. Forestry workers evacuated animals from the burning woods.
Defence Minister Ehud Barak ordered the military to make all its resources available to fight the fire and rescue victims.
The military said it sent soldiers and equipment, including helicopters, bulldozers, medics and army units.
After sundown, evacuation orders were issued for several communities, as well as a neighbourhood of Haifa and a third prison. Haifa University, at the edge of the stricken Carmel nature preserve, was evacuated, too.
Kibbutz Bet Oren, a collective village in the wooded area, suffered significant damage after its residents were evacuated, witnesses said.
The military emptied one of its prisons and three bases near the fire area. A psychiatric hospital was evacuated, and a nature resort in the middle of the forest sent all its guests home.
The men who perished aboard the bus were prison workers brought in as reinforcements from central Israel to assist in the rescue, said Yaron Zamir, a spokesman for the national prison service. He called it a "difficult, sad and incomprehensible day.''
Israel's president, Shimon Peres, expressed sorrow for the loss of life and praised firefighters trying to contain the blaze.
"They exemplify personal and superior bravery, and we are praying for a miracle,'' Peres said in a ceremony marking the Hanukkah holiday. "We pray for their safety. We pray for the cessation of the fire.''
Peres' office said he also spoke to the Palestinian prime minister, Salam Fayyad, who offered condolences.
President Barack Obama also offered condolences to families who lost loved ones in the fire, and pledged US help at a Hanukkah celebration at the White House.
