Fossil fuels might be going out of fashion, but a dispute over the right to drill for natural gas in the eastern Mediterranean has provoked fears that two NATO allies could come to blows.
Greece has welcomed the departure of a Turkish research ship from the area – but at the weekend, the Greeks announced that they were adding 15,000 troops to their armed forces.
“If you want peace, you must always be better prepared for war”, the Greek president explained.
She was speaking during a visit to a tiny Greek island just off the Turkish coast.
Our Foreign Affairs correspondent Jonathan Rugman was with her – and sent this report.