Athens, Jul 26 (IANS): The pilot and co-pilot of a firefighting plane have died after their aircraft crashed on Tuesday while battling a forest fire on the Greek island of Evia, the country's Defence Ministry said.

The victims were two Greek Air Force officers aged 27 and 34, according to an e-mailed press release. A three-day period of mourning in the Armed Forces has been announced in their memory, Xinhua news agency reported.

Greek President Katerina Sakellaropoulou and Prime Minister (PM) Kyriakos Mitsotakis expressed condolences to their families and colleagues.

"Our gratitude is enormous and our sorrow deep... Greece is mourning with you," Sakellaropoulou said.

"They sacrificed their lives to save other lives... In their memory, we continue the battle against nature's destructive forces," the PM said.

The bodies of the two men were retrieved from the crash site near the coastal town of Karystos after a search and rescue operation, the Greek national news agency AMNA reported. The Canadair plane was engulfed in flames after it crashed under yet unclear circumstances.

The two officers were the first fatalities of the wildfires that hit Greece this summer.

Firefighters have been battling over 500 wildfires that broke out across the country in the past two weeks, Greek government officials said on Monday.

The fire at Karystos was one of the largest raging since the weekend, the Fire Brigade said. The situation remained difficult in parts of the islands of Corfu and Rhodes, where major blazes burning since last week have caused extensive damage in forested zones and forced the evacuation of over 20,000 locals and tourists from several settlements.

Firefighters from ten countries have already joined their Greek counterparts, and further help is expected to arrive on Wednesday, the Fire Brigade said.

Greek authorities have warned of extreme risk of wildfires in several areas of the country due to the record-breaking heat. Greece has recently experienced its third heatwave this month.