Ukraine and Slovakia signed a natural gas transport deal Monday in what European officials hailed as the first step toward reducing Ukraine’s heavy dependence on Russian supplies that are now more costly and at risk of being cut off as hostilities escalate between the two former Soviet republics.

The agreement signed in the Slovakian capital, Bratislava, envisions annually rerouting more than 8 billion cubic meters of natural gas from Russia and other suppliers to Ukraine through Slovakian pipelines, according to a summary of the deal provided by the European Commission. That would make up almost a third of the 28 billion cubic meters of gas Ukraine imported from Russia last year in the event Moscow follows through on threats to cut off Kiev.

The plan was brokered by European Union officials with the stated objective of securing energy supplies for Ukraine as it struggles to deal with separatist aggression in its largely Russian-speaking eastern regions. But the deal may also reflect the West’s preference for targeting Russia’s financial institutions rather than its energy trade if further sanctions are imposed to punish Kremlin aggression against Ukraine.

EU states import about a third of their natural gas from Russia, and any boycott of gas or oil purchases from Moscow would hurt the European economies as much as Russia’s. Russia’s Gazprom monopoly operates so inefficiently and has extended so many differing contracts with Western European buyers that it barely breaks even on its gas sales to EU states and utilities, said Keith Crane, head of Rand Corp.’s environment, energy and economic development program.

Russia this month boosted the price of gas to Ukraine by more than 80 percent, rescinding a discount offered when the Kremlin was trying to deter then-President Viktor Yanukovich from entering into an economic association agreement with the European Union.

The Russian legislature revoked another discount this month that was part of Moscow’s lease arrangement for its Black Sea fleet naval base in Crimea. Russian troops seized the whole Crimean peninsula from Ukraine after Yanukovich was toppled in late February.