A firefighting helicopter with four crew aboard crashed into the sea off Greece on Wednesday, killing at least two people, according to Greek national broadcaster ERT.

"The Romanian pilot of the helicopter was found safe and sound by the Greek coastguard off Samos and taken to the island's hospital," a coast guard official told Agence France-Presse (AFP).

But she added that "two crew members – a Romanian and a Moldovan – were found unconscious in the water and efforts to resuscitate them are ongoing."

The fourth crew member, a Greek, was listed as missing and a coast guard rescue operation was underway to find him.

ERT later reported that two of the crew members had died.

A fire brigade official said the helicopter "was participating in fighting a forest fire on Samos," a mountainous island in the Aegean Sea.

The coast guard sent three patrol vessels and said two other boats were involved in the rescue operation.

The fire started around 2 p.m. (11 a.m. GMT), prompting authorities to dispatch three helicopters and five planes as well as some 50 firefighters.

But strong winds hampered their efforts as temperatures hovered around the 30 Celsius mark (86 Fahrenheit).

Greece regularly sees wildfires which last year killed three people and ravaged 130,000 hectares (1,300 square kilometers) of forest.

The Athens government this year requested support from European Union partners to cope with the expected threat and 250 firefighters were deployed in the country from Bulgaria, Finland, France, Germany, Norway and Romania.

Parts of Europe are currently experiencing a heat wave, with wildfires breaking out in Portugal, Spain, France and Turkey.

For Thursday, the Greek fire service issued the second highest warning level for several islands in the eastern Aegean, as well as the Attica region around Athens and the large islands of Euboea and Crete.