NIR ETZION, Israel — Israel’s rain-starved and wind-whipped north burned for a third day on Saturday as the police announced the arrest of two men they suspect of negligently starting the blaze. Exhausted firefighters, aided by airplanes and helicopters from around the world, meanwhile worked to contain the fire, which has killed 41 people and destroyed 12,500 acres of forest.

The authorities said they hoped to gain control of the fire by Sunday but feared it could take up to a week to extinguish it entirely.

The fire, which began near the port city of Haifa, spread overnight to this town and the nearby artist colony of Ein Hod, stray embers lighting up brush near banana plantations and eucalyptus trees and forcing fire trucks to scramble.

With electricity cut in many places, thick black smoke poured over the normally peaceful countryside, police commanders in face masks closed roads and yellow aircraft dumped loads of water and fire retardant on evacuated communities.

Prime Minister Benjamin Netanyahu took the unprecedented step of soliciting help from a dozen countries as Israel, often a provider of aid in catastrophes, sought to cope with the worst natural disaster in its history.

The country found itself ill equipped and short-staffed for the fire, leading to calls for senior resignations and official investigations. Internal and external critics said a country that prided itself on being ready for all eventualities, including war, was clearly not.

Micky Rosenfeld, a spokesman for the Israeli national police, would give no details on the suspects arrested other than to say he thought the fire had resulted from negligence.

Nearly all the deaths were from one busload of prison service cadets who were on their way on Thursday to evacuate a prison imperiled by the flames.

Aircraft and other aid arrived from friendly countries — Greece, Cyprus, France, Britain, Russia, the United States, Switzerland, Spain and Germany — as well as from those with more strained ties — Turkey and the Palestinian Authority in the West Bank.

Mr. Netanyahu phoned the Palestinian president, Mahmoud Abbas, on Saturday to thank him, their first direct contact since their peace talks were cut off more than two months ago over Palestinian objections to Israeli settlement building in the West Bank.

Mr. Netanyahu’s office reported that he expressed to Mr. Abbas his appreciation for the assistance and added that after this disaster Israel would obtain a fleet of firefighting aircraft and would make them available to the Palestinian Authority as well.

On Friday, Mr. Netanyahu held his first conversation in months with Prime MinisterRecep Tayyip Erdogan of Turkey to thank him for the two helicopters he sent. Turkey, once Israel’s closest Muslim ally, withdrew its ambassador and has cooled its relations with Israel after Israel’s war in Gaza two years ago and then an Israeli commando attack on a aid flotilla seeking to break Israel’s embargo of Gaza, an operation that killed nine Turks, including one with American citizenship.

Whether the disaster relief would ultimately help improve relations with the Turks or Palestinians remained unclear. Here in the north, ties between Israeli Arab villages and Jewish communities, sometimes strained, were also bolstered.

Eitan Menashe, police chief of the town of Zichron Yaakov near here, said in an interview that Arab villages had been offering their homes and much else to some of the 17,000 people who had been evacuated.

“They are being wonderful neighbors,” he said.