A lightning strike that damaged a key power station in Azerbaijan sparked a mass power cut Friday in Baku and other parts of the country, halting the capital's metro and causing traffic chaos, officials said.

Lightning hit the power plant at Mingacevir in northwestern Azerbaijan during a storm overnight, disabling several power units which were burned, the emergencies ministry said in a statement.

There was no electricity in the capital Baku as the city woke up in the dark while the metro also stopped working. Traffic lights also were not working in several places, causing huge traffic jams. However the city's airport was not affected.

There were no reports of any casualties as a result of the lightning strike at the coal and fuel-fired power station, which reportedly supplies almost half of the country's electricity needs.