Fire department officials in Greece have arrested two men for deliberately setting fires, while hundreds of firefighters battled wildfires that have killed at least 21 people in the past week.

One man was arrested on the island of Evia for allegedly setting fire to dry grass in the Karystos area. The fire department said the man confessed to having set four other fires in the area in July and August.

A second man, arrested in the Larissa area of central Greece, was also accused of intentionally setting fire to dry vegetation.

Officials have blamed arson for several fires in Greece over the past week. It remains unclear what sparked the country’s largest blazes, including one in the northeastern region of Evros, the location of nearly all the fire-attributed deaths, and another on the fringes of Athens.

A wildfire burns a forest near Alexandroupolis, in the northeastern Evros region of Greece. Photo / AP

Greece has been plagued by daily outbreaks of dozens of fires over the past week as gale-force winds and hot, dry summer conditions combined to whip up flames and hamper firefighting efforts. Firefighters were tackling 122 blazes at the weekend, including 75 that broke out in the 24 hours between Friday evening and Saturday evening, the fire department said.

Although most new fires were controlled in their early stages, some grew to massive blazes that have consumed homes and vast tracts of forest.

“Some ... arsonists are setting fires, endangering forests, property and above all human lives,” Climate Crisis and Civil Protection Minister Vassilis Kikilias said last week. “What is happening is not just unacceptable, but despicable and criminal.

“You will not get away with it. We will find you and you will be held accountable.”

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He said nine fires were set in the space of four hours on Thursday in the Avlona area on the northwestern fringes of Athens, which is one of the capital’s last green areas.

The Evros fire, Greece’s largest current blaze, has been burning for eight days near the city of Alexandroupolis, after causing at least 20 deaths. Authorities issued evacuation orders on Saturday for three villages in the area.

Firefighters found 18 bodies in a forest on Tuesday, one on Monday and another on Thursday. The 18 included two boys aged between 10 and 15. With nobody reported missing in the area, authorities believe the victims might have been migrants who recently crossed the border from Turkey.

Greece’s disaster victim identification team was activated to identify the remains and a telephone hotline was set up for potential relatives of the victims to call. A man reportedly trying to save his livestock from advancing flames in central Greece also died on Monday.

More than 290 firefighters, backed by five planes and two helicopters, were battling the Evros blaze. Another 260 firefighters, four planes and three helicopters were tackling the fire near Athens.

Another blaze broke out on the Cycladic island of Andros on Saturday, where an evacuation order for a village was issued. Firefighting reinforcements, including French crews with vehicles, were sent to Andros from other islands and the Greek mainland. A lightning strike was reportedly suspected as the cause.

Smoke from a wildfire on the outskirts of the Greek capital. Photo / AP

With firefighting forces stretched to the limit, Greece has called on other European countries for help. Germany, Sweden, Croatia and Cyprus sent aircraft, while dozens of Romanian, French, Czech, Bulgarian, Albanian, Slovak and Serb firefighters were helping on the ground.

Greece imposes wildfire prevention regulations, typically from the start of May to the end of October, to limit activities such as the burning of dry vegetation and the use of outdoor barbecues.

Since the start of this summer, fire department officials had arrested 163 people on fire-related charges, government spokesman Pavlos Marinakis said on Friday, including 118 for negligence and 24 for deliberate arson. The police made a further 18 arrests.