ALMATY, Jan 25 (Reuters) - Authorities and residents of the central Asian nations of Kazakhstan, Uzbekistan and Kyrgyzstan reported electrical power outages in major cities on Tuesday, but the cause was unclear.

The grids of the three ex-Soviet republics are interconnected, though Kazakhstan also has a connection to the Russian power grid it can use to cover unexpected shortages.

In Kazakhstan, outages were reported in the biggest city of Almaty and several major southern cities close to the Uzbek and Kyrgyz borders.

In a statement, Uzbekistan's energy ministry said it was working to resolve "a major power outage". (Reporting by Olzhas Auyezov; Additional reporting by Mukhammadsharif Mamatkulov in Tashkent; Editing by Clarence Fernandez)