By Alexander Tanas

CHISINAU (Reuters) - The prime minister of Moldova's separatist Transdniestria region said on Monday that the abrupt curtailment of Russian gas supplies that plunged the region into an energy crisis has also shattered both its exports and imports.

The cutoff, prompted by Ukraine's refusal to renew an agreement allowing Russian gas to transit through Ukraine, has led to daily blackouts in the pro-Russian region of some 350,000 people and disruptions in heating and water supplies.

Prime Minister Alexander Rozenberg told local media that the New Year cutoff had triggered a 43% decline in imports and a 60% plunge in exports in the region, which split from Moldova in the final days of Soviet rule.

"The steepest drop in the volume of export operations... has been registered in the metals sector, in manufacture of machines and in the chemical industry," he said. "Exports of cement have been completely stopped."

Transdniestria depends heavily on assistance from Moscow and its leaders acknowledge that the Russian gas it has long received was provided free of charge as "humanitarian assistance".

The gas cutoff affects operations at a thermal plant that provides electricity both for Transdniestria and much of the area controlled by the central Moldovan government. Its operations have been switched to coal, and Ukraine, Moldova's eastern neighbour, has offered to provide supplies.

Moldovan President Maia Sandu, who has spearheaded the country's drive to join the EU, called a meeting of Moldova's Supreme Security Council on Tuesday to discuss energy. Both Moldova and Transdniestria have proclaimed states of emergency.

Much of Transdniestria's industry has been forced to close or obliged to operate at night, when there is less strain on the power grid. Among the factories closed are a cement plant and a steel mill in the town of Rybnita, with the latter accounting for 35% of the region's budget revenue.

The region's separatist authorities last week said energy savings had enabled them to reduce rolling blackouts from eight hours a day to three by the weekend. But a blackout of five hours had been announced for Monday.

Moldova, which denounces Russia's invasion of Ukraine, says Moscow fomented the crisis and has suggested shipping gas on a route through Turkey, Bulgaria and Romania.

Russian gas giant Gazprom said it will provide no supplies until Moldova settles arrears it estimates at $709 million, a figure disputed by Moldovan authorities.

Transdniestria's leaders say Moldova has done nothing to ease the crisis and reject any notion that Moldova's government has offered to help purchase power from Western Europe.

More than 30 years after Transdniestria waged a brief war against the newly independent Moldovan state, the region continues to exist alongside Moldova with little turmoil. But 1,500 Russian "peacekeepers" remain in the territory and efforts to resolve the separatist dispute have made little headway.

(Reporting by Alexander Tanas, writing by Ron Popeski; Editing by Bill Berkrot)