Turkey Blackout: Massive Power Outage Plunges Country Into Darkness A power outage has caused problems in parts of the country.

 -- A massive nationwide power outage has struck Turkey today, causing travel chaos in major cities and leaving roughly three-quarters of the country with limited electricity.

The blackout -- the worst in Turkey for over a decade -- has affected around 40 provinces. In Istanbul traffic lights and much of the city’s subway went dark after power stopped around 10:30 a.m., officials said.

Local airports were forced to close and flights are disrupted.

Engen Bas, an Istanbul-based journalist working for ABC News, said that most major public facilities were running on backup generators and that Internet coverage was also down in some places.

The reason for the blackout is so far unexplained. With officials only able to speculate, rumors of cyber-attacks and terror threats quickly appeared. Turkish prime minister, Ahmet Davutoglu, said that the most likely cause was problems with transmission lines but said he could not rule out terrorism.

“This is not an incident we see frequently,” said energy minister, Yaner Yildiz, currently on an official visit to Slovakia.

“Whether or not terrorism is a high possibility or a low I can’t say at this stage. I can’t say either whether it’s a cyber-attack,” he told Turkish TV.