HAIFA, Israel — Foreign firefighters and aircraft poured into Israel today in an unprecedented wave of international assistance as the country battled a huge forest fire that has killed at least 41 people and displaced thousands.

Firefighters struggled for a second day to contain the inferno as flames spread through one of the country’s few natural forests to the outskirts of Israel’s third-largest city, Haifa. One of the main highways was closed to traffic as smoke billowed toward the Mediterranean coastline.

“The size of the fire is huge, the wind is very strong and there is a problem accessing the mountains and valleys,” said Yoram Levi, a spokesman for Israel’s fire and rescue service. “We don’t have big aircraft that can carry a large amount of water.”

The shortfall prompted Israel to issue a rare cry for nonmilitary 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.