Some two-thirds of the normal electricity supply from Ukraine went off around 1900 GMT, ITAR-TASS cited the local electricity distributor as saying, plunging into darkness major cities as Yalta and Sevastopol, the home of the Russian Black Sea Fleet.
Supplies to the peninsula which is dependent upon Ukraine for 80 per cent of its electricity were eventually restored, said Crimenergo, but there was no explanation from Ukraine as to the reason for the outage.
"It is the latest act of sabotage by the Ukrainian authorities, this time aimed at disrupting preparations for the schools' reopening for the beginning of the school year," Sergei Aksyonov was quoted as saying by RIA-Novosti news agency.
No comment was immediately available from the Ukrainian authorities.