Almost 2 million people on the Crimean peninsula were left without light or heat overnight into yesterday after two explosions damaged power lines from Ukraine, local authorities said.

Ukraine's Interior Ministry said preparations for repair work were underway after two power lines were blown up on Saturday night and two other power lines went out of service because of damage to electricity towers, Russian state news agency Tass reported. Authorities managed to partially restore energy supplies in the bigger cities with the help of their own power plants, gas turbines and diesel generators, spokesman Michail Scheremet told Tass. Scheremet added that Crimea's emergency fuel supplies for backup generators will suffice for at least 30 days.

The Crimean peninsula, which according to international law is part of Ukraine, gets 70 percent of its electricity supply from mainland Ukraine.

Crimean Tartar and Ukrainian activists have been blocking the supply of goods to the peninsula for more than two months. They have also been calling on the leadership in Kiev to cut energy supplies in an attempt to force the release of Ukrainians held in Russia as well as a lifting of the entry ban on Crimean Tartar politicians.

The power lines in the Kherson area had already been damaged. Security forces clashed with protesters as they tried to give workers access to fix them. The authorities on the peninsula, which has been occupied by Russia since 2014, called a state of emergency after the large-scale power cuts. The Crimean leadership also set up a crisis management group.

Reinstating energy supply to the region could take around two days, staff of the Ukrainian energy company Ukrenergo were quoted as saying. The energy ministry in Kiev said that 40 percent of energy supplies were threatened in the southern Ukrainian regions of Kherson and Mykolaiv. Two districts had no power.