Publishedduration9 minutes agoshareSharenocloseShare pagelinkCopy linkAbout sharingimage copyrightReutersimage captionThe blackout affected major cities nationwide, including Karachi

Electricity is gradually being restored in some areas of Pakistan following a huge power cut across the country, with every city reporting outages.

Homes nationwide were suddenly plunged into darkness from about midnight.

Officials appealed for calm but warned that it could take several hours before electricity is fully restored.

Power cuts are not uncommon in Pakistan. Essential facilities such as hospitals often use diesel-fuelled generators as a back-up power supply.

"A countrywide blackout has been caused by a sudden plunge in the frequency in the power transmission system," Pakistan's Power Minister, Omar Ayub Khan, wrote on Twitter in the early hours of Sunday.