Turkey is heading for make-or-break elections this weekend, with energy a key issue as President Recep Tayyip Erdogan faces the possibility of being ousted for the first time in more than 20 years.

The elections will be closely watched by Europe, with Turkey having an increasing key role as a transit country for oil and gas supplies as the European Union wrestles with ongoing energy-security concerns and calls to impose sanctions on countries viewed as aiding Russian oil and gas exports.