A massive power outage hit dozens of Turkish cities and provinces Tuesday, bringing public transportation services to a halt and disrupting businesses that have no backup power.

Prime Minister Ahmet Davutoglu said officials are investigating all possible causes, including a terrorist attack, for the electricity shutoff across Turkey, according to the Hurriyet Daily News .

Energy Minister Taner Yildiz said teams are working to determine the cause of the blackout, ruling out claims that the country is suffering an energy shortage.

Yildiz released a statement saying a problem occurred with the main distribution lines and that the cut likely originated in the Aegean region, according to Hurriyet. "I also cannot say whether or not there was a cyber attack," he said.

The Turkish newspaper also quotes officials who say a technical problem in power transmission lines led to the massive outage.

At least 44 provinces throughout Turkey were affected by the outage, the biggest in 15 years. Metro and tram services in Ankara and Istanbul and three other major cities ground to a halt, according to The Associated Press .

Reuters reports that people carrying jerry cans were lining up at gas stations to buy fuel for generators and that road intersections were clogged with traffic. The news agency said that several hours after the outage hit, power had been mostly restored in the major cities.

Meanwhile, Hurriyet reports that the hashtag #BuradaElektrikYok, which means "There is no electricity" in Turkish, climbed to the top of the global trending topics list on Twitter Tuesday.

Copyright 2016 NPR. To see more, visit http://www.npr.org/ .