SOCHI, Russia (Reuters) - Russian President Vladimir Putin oversaw the launch of a fourth and final line supplying electricity from Russia to Crimea on Wednesday, saying the project had broken an energy blockage he accused Kiev of imposing on the peninsula.

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Russia annexed Crimea from Ukraine in March 2014. Moscow has since faced international condemnation and the logistical challenges of sustaining a region that depended on Ukraine for much of its supplies and has no land border with Russia.

In November last year, Crimea was plunged into darkness when unidentified individuals blew up the power lines through which the peninsula received the bulk of its power from the Ukrainian grid. Kiev denied responsibility for the sabotage.

“I congratulate all of you on the completion of building this energy bridge which has tied Crimea to Russia,” Putin said in a video link from his Black Sea residence in Sochi, Russia, addressing workers and engineers on the power line.

“We managed to break through the energy blockade of Crimea within a brief period of time, and we will likewise do away with any other blockade against Russia, should someone wish to test us again,” said a visibly upbeat Putin, accompanied by Russian Energy Minister Alexander Novak.

The energy bridge is a series of cables along the seabed across the Kerch Strait that separates Russia from Crimea.

The new line will bring total power supplies from Russia to Crimea to 800 megawatts, which combined with the peninsula’s own capacity should be enough to satisfy its demand.

Novak said the peninsula would have enough electricity to see it through the holiday season, when tourists swell the population and provide Crimea with a major source of revenue.

The peninsula will have complete power self-sufficiency after completion of power stations that are under construction in the Crimean cities of Sevastopol and Simferopol.

Russia denies annexing Crimea which it took over after street protests in the Ukrainian capital of Kiev chased a pro-Moscow president from power.

It says residents there voted to become part of Russia, and that Moscow acted to protect their freely-expressed will.

The next phase of Moscow’s project to end Crimea’s isolation is the construction of a 19 km (12 mile) road and rail bridge across the Kerch Strait.

The $3.2 billion project will be the longest of its kind in Europe and is scheduled for completion at the end of 2019.