(ATHENS, Greece) — Firefighters struggled Thursday against strong winds and hot, dry conditions to tame multiple wildfires ravaging Greece, including one in the country’s northeast that officials say is the largest ever recorded in the European Union.

The wildfires have left 20 people dead over the last week. Eighteen of those, including two boys aged between 10 and 15, are believed to be migrants who crossed the nearby border with Turkey. Their bodies were found by firefighters near a shack in a burnt forest area near Alexandroupolis in northeastern Greece. Sixty firefighters have been injured, fire department spokesman Ioannis Artopios said.

The wildfire in the Alexandroupolis region, burning for a sixth day, combined with smaller fires to create a massive inferno that has consumed homes and vast tracts of forest and triggered multiple evacuations of villages and of the city’s hospital.

With more than 730 square kilometers (282 square miles) burned, the combined blazes “are now the largest wildfires on record the EU has faced,” European Commissioner for Crisis Management Janez Lenarcic said on X, the social media platform formerly known as Twitter.

“We must continue strengthening national & collective prevention and preparedness efforts in view of more brutal fire seasons,” he tweeted.

Elsewhere in Europe, fires on Tenerife in Spain’s Canary Islands, northwestern Turkey near the border with Greece, Portugal and Italy were being brought under control, officials said.

Firefighters in Greece were battling dozens of other fires, including a major blaze on the outskirts of Athens that scorched homes and encroached on one the last green areas near the Greek capital, the national park on Mount Parnitha. On Wednesday alone, firefighters battled 99 separate blazes across the country, authorities said.

Greece’s Climate Crisis and Civil Protection Minister Vassilis Kikilias said arson was to blame for some of the blazes near Athens.

“Some … arsonists are setting fires, endangering forests, property and above all human lives,” Kikilias said in a televised statement. “What is happening is not just unacceptable but despicable and criminal.”

The minister said nine fires had been set in the space of four hours Thursday morning in the area of Avlona, in the northern foothills of Mount Parnitha.

“You are committing a crime against the country,” Kikilias said. “You will not get away with it. We will find you, you will be held accountable to justice.”

With firefighting forces stretched to the limit, Greece has asked other European countries for assistance. Germany, Sweden, Croatia and Cyprus sent aircraft, while dozens of Romanian, French, Czech, Bulgarian and Albanian firefighters have been helping on the ground.

Artopios, the Greek fire department spokesman, said 260 firefighters, including more than a dozen from France, were battling the Parnitha fire supported by 10 planes and 11 helicopters. Bulgarian, Albanian, Romanian and Czech firefighters with vehicles were helping in the Alexandroupolis fire.

With their hot, dry summers, southern European countries are particularly prone to wildfires. European Union officials have blamed climate change for the increasing frequency and intensity of wildfires in Europe, noting that 2022 was the second-worst year for wildfire damage on record after 2017.

In Spain’s Tenerife, a fire that has scorched 150 square kilometers (58 square miles) was being brought under control.

Canary Island regional President Fernando Clavijo said Thursday the blaze had “not gained a single square meter" for the first time in over a week.

He said firefighters hope to declare the fire totally under control later Thursday, but warned that high afternoon temperatures could ignite more pockets of fire. Of the 12,000 people forced to evacuate their homes earlier in the week, only about 200 were still unable to return.

In Turkey, firefighters in the northwestern Canakkale province on Thursday brought a wildfire under control less than 48 hours after it erupted amid high temperatures and strong winds, Turkish Forestry Minister Ibrahim Yumakli said.

Yumakli said the fire, which had forced the evacuation of 11 villages, had affected 40 square kilometers (15 square miles) including 14 square kilometers (5.4 square miles) of agricultural land.

A firefighting volunteer who was injured and six other people who suffered from smoke inhalation were being kept under observation in hospitals, Yumakli said.

“We are extremely happy that there was no loss of life,” Yamukli said. “However, we are heartbroken for other creatures of the ecosystem that were affected.”

Shipping traffic through the Dardanelles Strait, a major maritime thoroughfare linking the Aegean Sea with the Sea of Marmara, was being partially restored to one lane only, after being completely suspended as fire-dousing aircraft use the waterway to pick up water.

Yumakli said another fire in central Turkey has also been brought under control and there were no other active wildfires in the country Thursday.

Two large fires in Portugal and a smaller one in Italy were brought under control by Thursday, those countries’ authorities said, but temperatures - and the risk of new fires - remained high.