Russia is to send firefighting aircraft to help Greece combat forest fires raging amid record high temperatures.
The Russian Ilyushin can carry a huge cargo of water
Five aircraft will be sent to Greece on Friday in response to an appeal by Prime Minister Costas Karamanlis, Russia's Itar-Tass news agency said.
Greek emergency crews are fighting fires in at least 15 parts of the country, officials said. There are also fires in Bulgaria, Italy and Macedonia.
Hundreds of people have died in sweltering heat in South-East Europe.
Cooler weather is expected to arrive over the weekend.
Prime Minister Karamanlis earlier telephoned Russian President Vladimir Putin asking for help in fighting the fires.
According to Itar-Tass, Russian aircraft due to arrive in Greece include the Il-76 "water bomber", capable of discharging 42 tonnes of water from the air.
Other aircraft reportedly in the group include an amphibious plane and three helicopters, each capable of carrying of five tonnes of water.
Russia has already sent a firefighting helicopter to Greece, the agency says.
Already this summer, Greece has been supplied with extra firefighting planes from its European Union partners, the BBC's Malcolm Brabant reports from Athens.
Greece faces "a particularly difficult situation" because of the "simultaneous appearance of a large number of forest fires and unprecedented weather conditions", Mr Karamanlis' office said.
The worst blazes in Greece were reported near Aegio in the south, on the island of Cephallonia and near the border with Macedonia and Albania.
Hundreds of people, including tourists, have been evacuated from areas at risk from fires in the Peloponnese and Cephallonia.
At least two people died after being trapped in fires in Greece on Wednesday.
One of the biggest blazes, near the southern town of Aegio, destroyed homes in at least eight villages and forced the temporary closure of the highway linking Athens to the port of Patras.
Greece's electricity grid has been close to breaking point as demand has soared. Searing temperatures have also evaporated rivers used to create hydro-electric power.
The authorities have urged people to limit their use of air conditioners to avoid putting a strain on electricity supplies.
Meanwhile in northern Europe, the UK has seen unseasonably heavy rainfall and severe flooding.
South-East Europe's heat and the UK's wet weather have both been blamed on changes in the jet stream - a seasonal band of air from the Atlantic that has taken a more southerly path across Europe this year.
In a 'normal' summer, the Atlantic jet stream directs areas of low pressure, which bring cloud and rain, to the north of the UK. High pressure systems over Europe and the Atlantic bring warm, settled conditions.
Pressure chart: 29/6/06. Source: Met Office
This summer, the jet stream is flowing further south, allowing low pressure systems to sweep straight over the centre of Britain. It is also pulling in warmer air from the sub-tropics and Africa, which is sweeping over south-eastern Europe.
Pressure chart: 24/07/07. Source: Met Office