Firefighters found the burnt bodies of 18 people, believed to have been migrants who had crossed the nearby border with Turkey, in an area of northeastern Greece ravaged by a major wildfire that raged for a fourth day Tuesday.

The discovery in the Avantas area near the city of Alexandroupolis came as hundreds of firefighters battled dozens of wildfires across the country amid gale-force winds. On Monday, two people died and two firefighters were injured in separate fires in northern and central Greece.

With their hot, dry summers, southern European countries are particularly prone to wildfires. Another major blaze was burning across Tenerife in Spain's Canary Islands for a week, although no injuries or damage to homes was reported.

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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 Greece, police activated the country's Disaster Victim Identification Team to identify the 18 bodies, which were found near a shack in the Avantas area, fire department spokesman Ioannis Artopios said.

"Given that there have been no reports of a missing person or missing residents from the surrounding areas, the possibility is being investigated that these are people who had entered the country illegally," Artopios said.

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Alexandroupolis is near the border with Turkey, along a route often taken by people fleeing poverty and conflict in the Middle East, Asia and Africa and seeking to enter the European Union.

Greek President Katerina Sakellaropoulou voiced deep sorrow at the deaths.

"We mourn their loss ... (and) the destruction of nature, (and) we are saddened by our inability to avert it," she said in a statement. "We must urgently take effective initiatives to ensure that this bleak reality does not become the new normality."

Avantas, like many nearby villages and settlements, had been under evacuation orders, with push alerts in Greek and English sent to all mobile phones in the region.

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Overnight, a massive wall of flames raced through forests toward Alexandroupolis, prompting authorities to evacuate eight more villages and the city's hospital as flames reddened the sky.

About 65 of the more than 100 patients in the hospital were transported to a ferry boat in the city's port, while others were taken to other hospitals in northern Greece. The ferry later took 26 the patients to the port town of Kavala, to be transferred to another hospital.

Deputy Health Minister Dimitris Vartzopoulos, speaking on Greece's Skai television, said smoke and ash in the air around the Alexandrouplolis hospital were the main reasons behind the decision to evacuate the facility.

"We evacuated within four hours," he said.

The coast guard said patrol boats and private vessels evacuated an additional 40 people by sea from beaches near Alexandroupolis.

In the northeastern Evros border region, a fire was burning through forest in a protected national park, with satellite imagery showing smoke blanketing much of northern and western Greece.

New fires broke out in several parts of the country Tuesday, including in woodland northwest of Athens and an industrial area on the capital's western fringes.

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Small explosions echoed from the industrial area of Aspropyrgos as flames reached warehouses and factories. Authorities shut down a highway and ordered the evacuation of nearby settlements.

With firefighting forces stretched to the limit, Greece appealed for help from the European Union's civil protection mechanism.

Five water-dropping planes from Croatia, Germany and Sweden, and a helicopter, 58 firefighters and nine water tanks from the Czech Republic flew to Greece Tuesday, while 56 Romanian firefighters and two aircraft from Cyprus arrived Monday. French firefighters helped tackle a blaze on the island of Evia on Monday.

"We are mobilizing actually almost one-third of the aircraft we have in the rescEU fleet," said EU spokesman Balazs Ujvari.

The fire risk level for several regions, including the wider Athens area, was listed as "extreme" for a second day Tuesday. Authorities banned public access to mountains and forests in those regions until at least Wednesday morning and ordered military patrols.

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In Spain, firefighters battled to control a wildfire burning for a week on the popular Canary Islands tourist destination of Tenerife. It is estimated that the blaze, which has scorched 150 square kilometers (59 square miles), has already burnt a third of Tenerife's woodlands.

More than 12,000 people were evacuated during the past week. Authorities said Tuesday that 1,500 have been able to return to their homes. Authorities have described the fire as the worst in decades on the Atlantic archipelago.

Large parts of Spain were under alert for wildfires as temperatures reached more than 38 degrees Celsius (100 degrees Fahrenheit). While Spain's south often has extremely high temperatures, the country's weather agency issued an alert for the northern Basque Country, where temperatures were forecast to reach 42 degrees Celsius (107 degrees Fahrenheit) Wednesday.

Greece's deadliest wildfire killed 104 people in 2018, at a seaside resort near Athens that residents had not been warned to evacuate. Authorities have since erred on the side of caution, issuing swift mass evacuation orders whenever inhabited areas are threatened.

Last month, a wildfire on the island of Rhodes forced the evacuation of some 20,000 tourists. Days later, two air force pilots were killed when their water-dropping plane crashed while diving low to tackle a blaze on Evia.

In Italy, authorities evacuated 700 people from homes and a campsite on the Tuscan island of Elba after a fire broke out late Monday, while in Turkey authorities evacuated nine villages in northwestern Canakkale province.

According to the Italian Society of Environmental Geology, more than 1,100 fires in Europe this summer have consumed 2,842 square kilometers (about 1,100 square miles), well above an average of 724 fires a year recorded from 2006-2022. The fires have removed wooded areas capable of absorbing 2.5 million tons of carbon dioxide a year.

"When we add the fires in Canada, the United States, Africa, Asia and Australia to those in Europe, it seems that the situation is getting worse every year," said SIGEA president Antonello Fiore.