Moscow, November 25

Tensions between Russia and Ukraine escalated further today as Ukraine decided to stop buying Russian natural gas hoping to rely on supplies from other countries and closed its airspace to its eastern neighbour.

Russia’s annexation of Crimea from Ukraine in March 2014 and its support for separatist rebels in the east brought relations between the two countries to a post-Soviet low. The fighting between Russia-backed rebels and government forces in eastern Ukraine killed more than 8,000 people and left parts of Ukraine’s industrial heartland in ruins.

Ukraine still has no access to the territories under rebel control as well as hundreds of kilometers of the Ukrainian border with Russia.

Ukraine has since been trying to cut its dependence on Russia gas, buying from European nations that had bought it from Russia at a lower price.

Russia’s state-controlled gas company, Gazprom, said today that it stopped sending gas to Ukraine this morning and will supply no more because Ukraine has not paid in advance for more deliveries.

Ukrainian said it was its own decision to stop buying gas from Russia after it was offered better prices from other European countries. Those other countries import gas from Russia but can pipe it back to Ukraine.

The stoppage comes less than two months after the two countries signed an EU-brokered deal ensuring supplies through March. Under the deal, Russia lowered the price it charged Ukraine to the same level granted to neighbouring countries, from $251 per 1,000 cubic meters to about $230.

Gazprom CEO Alexei Miller today warned Ukraine and Europe of possible gas disruptions following the cut-off. Russia uses Ukraine’s pipelines to transport a part of its gas deliveries to other European countries.

Ukraine’s “refusal to buy Russian gas threatens a safe gas transit to Europe through Ukraine and gas supplies to Ukraine consumers in the coming winter,” Miller said.

The Gazprom chief said Ukraine had been buying up gas to store for the coming winter in the past two months but claimed it was not enough to get it through the winter.

Past gas disputes between Russia and Ukraine have led to cutoffs. One standoff in 2009 caused serious disruptions in shipments to EU countries in the dead of winter.Temperatures in Ukraine, where most homes rely on gas for central heating, were below freezing this morning.

Ukrainian Prime Minister Arseny Yatsenyuk also announced that his government had decided to close the country’s airspace to all Russian planes as “an issue of the national security as well as a response to Russia’s aggressive actions.’

Ukraine last month banned all Russian airlines from flying into Ukraine but Russian planes were allowed to fly over its territory.