A major technical fault in Pakistan’s electricity generation and distribution system caused a massive power cut that plunged the country into darkness late on Saturday night, the energy minister said.

Hours after the incident, Omar Ayub said on Twitter that power was being restored in phases, starting with Islamabad.

Later on Sunday, he he said that power had been restored to much of the country.

The blackout was initially reported on social media by residents of major urban centres, including Karachi, Lahore, Islamabad and Multan. The minister and his spokesman then took to Twitter to update the country.

Mr Ayub urged people to be patient. He said the cause of the incident was being investigated and work was being done to fire up Pakistan’s main Tarbela power station in the north-west, which would lead to a restoration of power in the rest of the country in phases.

He told a news conference on Sunday that the Guddu power plant in southern Sindh province developed a fault at 11.41pm on Saturday, which triggered the shutdown of other power plants in seconds.

Later, Zafar Yab, spokesman for the Ministry of Energy, said the Tarbela and Warsak plants, both in north-western Khyber Pakhtunkhwa province, had come back online and power was being restored to the transmission system.

However, he added that restoration of power to all areas of the country would take some time.