A damaged electricity pylon near the village of Chonhar in Ukraine’s Kherson region. Crimea was left without power supplies from Ukraine for a second day Monday after the line to the Russia-annexed peninsula was attacked over the weekend. (Reuters)

The Ukrainian government on Monday abruptly banned freight traffic to the Crimean Peninsula as tensions with Russia over the disputed territory have reignited into threats of a full-blown trade war.

Russia annexed Crimea in March last year, but the peninsula remains dependent on infrastructure and deliveries from Ukraine for supplies of electricity, water and food.

On Monday, Ukrainian President Petro Poroshenko proposed suspending the dispatch of cargo to the peninsula while his government “defines the model for Ukraine’s future relations with the temporarily occupied territory of Crimea,” a presidential statement read. Ukraine’s cabinet later approved the decision with no time limit.

The ban came two days after power to Crimea was cut in an apparent act of sabotage, as pylons conveying electricity to the peninsula were blown up. ­Suspicion quickly fell on pro-Ukrainian activists calling for a blockade of Crimea, who had been protesting near the site of the attack.

A police officer controls traffic near lights disabled by the power cut in Simferopol, Crimea, on Monday. Pro-Ukrainian activists prevented repairs to sabotaged power lines for a second day as Kiev imposed a freight blockade on the peninsula. (Pavel Rebrov/Reuters)

Ukraine’s government pledged Monday to return power to Crimea as soon as possible, but it also said it would review whether to continue supplying electricity to the region at all next year. On Monday, activists were preventing repairs to the damaged pylons for a second day.

While fighting has significantly decreased between Russian-backed separatists and Ukraine’s army in the country’s east, the two nations have steadily cut trade, cultural and travel ties in the course of a painful separation that shows no signs of slowing.

Russia is set to introduce sanctions banning the import of most Ukrainian food products starting in January. Moscow has described the move as retaliation for Ukraine joining European Union sanctions against Russia this year.

Ukrainian Prime Minister Arseniy Yatsenyuk on Monday declared that Ukraine will retaliate against the planned Russian sanctions.

“Each Russian decision to impose an embargo against Ukraine will have an analogous Ukrainian decision about the introduction of an embargo against Russia,” Yatsenyuk said in a television appearance.

Russian and Ukrainian airlines last month also halted all direct flights between the two countries, a decision that is ­expected to adversely affect almost 700,000 passengers annually.

Russia is trying to wean Crimea off dependence on Ukraine, but building infrastructure takes time. A planned bridge from mainland Russia to Ukraine across the Kerch Strait is not expected to be finished for several years. Russia began laying power cables across the strait in August.

Russian Deputy Prime Minister Dmitry Kozak said Monday that Russia would “speed up the construction of the power bridge,” adding that supply deliveries should improve by mid-December.

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