Two security guards were killed in a suspected "terrorist act" when an explosion struck a hydroelectric power station in the Kabardino-Balkaria region of Russia's North Caucasus on Wednesday, officials said.
Russia is trying to contain an upsurge of attacks by rebels in the mainly Muslim provinces on its southern flank who took their war to the Russian heartland in March with suicide bombings on the Moscow metro that killed at least 40 people.
A powerful blast ripped through part of the Baksanskaya plant, Rushydro HYDR.MM, Russia's largest hydroelectric power producer which runs the station, said in a statement.