Greece has ordered electricity workers back to their jobs, threatening them with arrest if they continue with strikes that have caused power cuts across the country in the middle of its tourist season.

The move came after workers at Public Power Corp (PPC), Greece's biggest power producer, defied a court ruling issued late on Friday deeming their strike action illegal. Protesting against government plans to sell part of PPC in 2015, workers initiated a series of 48-hour strikes. Unions say the sale will push up electricity prices.