At least 150 houses have been destroyed by a raging fire that surrounded a monastery and a dozen villages on the Greek island of Evia, one of over 100 blazes burning in the country.

Firefighters were also continuing to battle a blaze near Athens on Thursday morning, while the mayor of Olympia, the birthplace of the Olympic Games, pleaded for help as flames threatened the site.

The blazes erupted as Greece is in the grip of a heatwave.

“We’re waging a battle of the titans!” deputy minister for civil protection Nikos Hardalias told journalists. “The hardest is still to come.”

Experts have warned that global heating is increasing both the frequency and intensity of such fires.

On Evia, the huge flames leaping up from the forest could be seen from the sea. Firefighters said it was a difficult blaze to control on an island of rolling hills with little visibility.

Three monks from Saint David Monastery had refused to leave, they added, but everyone had been evacuated from nearby villages.

“We’re suffocating due to the smoke,” one of the monks told the ANA news agency by phone, describing flames 30 to 40 metres (100 to 130 feet) high surrounding the monastery.

Police told AFP they would force the monks to evacuate if their lives were in danger. Around 85 people gathered on a beach were evacuated on five boats.

Some 100 firefighters backed by seven helicopters and water-bombing planes were fighting the blaze, civil protection officers said.

But local politicians denounced the lack of resources.

“We are asking the authorities to reinforce the air and land forces to so as not to risk human lives,” Giorgos Tsapourniotis, the mayor of Limni, told ANA news agency.

Argyris Liaskos, deputy mayor of Mantoudiou, told Skai TV that no air support had been deployed there to tackle the fires. “At least 150 houses have burned,” he said.

According to Hardalias, Greece has faced a total of 118 fires in the last 24 hours as temperatures soared above 40C (104F).

Evia island is some 200km (125 miles) away from Athens, where more than 500 firefighters, a dozen water-bombing planes and five helicopters battled another wildfire on the outskirts of the city.

The blaze started on Tuesday in a pine forest at the foot of Mount Parnitha, one of three ranges that surround the Greek capital, sending plumes of dark, acrid smoke over Athens and leaving carcasses of burnt-out houses in its wake.

Around a dozen houses have been destroyed in the flames, and dozens of businesses, bars and holiday accommodation severely damaged in the suburb of Varybombi, 30km (20 miles) north-west of Athens, officials said.

But by Wednesday afternoon, the blaze was coming under control, Hardalias said.

Authorities in Athens have recommended residents stay indoors and wear a mask to protect against the ash and smoke.

Dozens of people had contacted the emergency services complaining of breathing difficulties.

In Olympia, around 100 firefighters were battling the blaze, aided by three helicopters and two planes.

“Everything that can be done to protect from the flames the museum and the archaeological site, where the Olympic games started, has been done,” said culture minister Lina Mendoni on Wednesday evening.

Earlier, the mayor of Olympia, Giorgos Georgopoulos, had called for more aerial support.

The European Union’s crisis management commissioner said it would help, and Cyprus and Sweden were both sending two water-bombing planes to help battle the fires.