A breakdown at a power station in northwest Turkey caused power cuts on Saturday in the country’s largest city, Istanbul, and several others.

Subway lines and trams stopped working in Istanbul, a city of 17 million, causing traffic jams on the main roads. With heating systems shut down, residents were left in freezing temperatures.

"It’s a technical problem, and we expect the issue to be resolved soon," Istanbul Governor Huseyin Avni Mutlu told the state-run Anatolian news agency.

Energy Ministry officials said the cut had been caused by a system failure in a gas-fired power plant in the northwestern industrial city of Bursa.

The outage began at around 1 p.m. (11:00 GMT) in Istanbul.

Also affected were the cities of Sakarya, Kocaeli, Tekirdag, Kirklareli and Edirne.