Dozens of provinces across Turkey have been hit by a major power blackout on Tuesday, March 31.
According to Turkish officials, a break in connections with mainland Europe could be to blame for the outage.
The cuts affected power stations and public transport, including Istanbul’s tram and metro systems.
A crisis centre has been set up at the energy ministry.
PM Ahmet Davutoglu has said all possible causes are being examined, including terrorism. The outage hit at 10:36 local time on Tuesday morning.
By early afternoon the Turkish Electricity Transmission company said only 15% of Istanbul and Ankara had power. Istanbul’s transport company said all of its lines were back up and running.
Turkish TV reported that power had been re-established in the cities of Edirne, Tekirdag, Erzurum and Trabzon.
“Our main target right now is to restore the network. This is not an incident that we see frequently,” Energy Minister Taner Yildiz told Turkish media.
Turkey suffers from sporadic power outages but locals say they cannot remember such a nationwide cut for a generation.
One of the few cities unaffected by the power cut was Van in eastern Turkey, where electricity is supplied from Iran.