Firefighters in Greece were working early Monday to contain a major and fast-spreading wildfire that broke out near Athens a day earlier, which has damaged buildings and produced flames more than 80 feet tall, the authorities said.

The fire started on Sunday afternoon in Varnava, a town less than 30 miles north of Athens by road, and spread rapidly within minutes because of high winds, Greece’s national fire service said. Evacuation orders were later issued for residents in several communities.

The fire then spread on Sunday evening, in some cases between residential buildings, Col. Vassilios Vathrakogiannis, a spokesman for the fire service, said in a news release. He said the fire also threatened Lake Marathon, a reservoir serving Athens. The fire service warned of strong winds.

Greece is experiencing an exceptionally hot and dry summer, and its national fire service has battled wildfires in several parts of the country. The national authorities said that several areas, including Athens, would likely face “extreme fire risk” — the highest level of risk in the country’s five-tier system — on Monday.

Forty wildfires broke out in Greece in a 24-hour period over the weekend, Colonel Vathrakogiannis said in the news release on Sunday, adding that 33 of those fires were immediately brought under control.

“Today has been a highly challenging day,” he said.

He later said that the response to the wildfire in Varnava involved 400 firefighters, a large number of volunteers, forest commando teams, and 16 aircraft and 13 helicopters. He did not say how large the fire was.

The New York Times