Russia on Wednesday stopped delivering natural gas to Ukraine days after nationalists and ethnic Crimean Tatars destroyed pylons carrying electricity to the Black Sea peninsula, leaving the Russian-annexed territory in the dark.

It is the fourth time since 2006 that Russia has cut off gas supplies to its former satellite state.

Gazprom, the Russian gas monopoly, blamed Ukraine, saying it had failed to pay for deliveries in advance.

But only two months ago, the two stuck a deal under European auspices that would have seen Gazprom supply two billion cubic meters of gas to Ukraine at a price of $500 million.

Around half the natural gas Russia sells to European Union member states is piped through Ukraine.

Tit for tat

The Russian energy minister, Alexander Novak, said this week the Kremlin was also considering cutting off coal exports to Ukraine.

Kiev, in turn, said it would implement an economic blockade of the Crimea and closed its airspace to all Russian planes.

The two former Soviet states last month banned each others’ airliners, but Russian commercial jets were still permitted to fly over Ukrainian territory.

Crimea cut off

The escalation of the economic war between Ukraine and Russia comes as Russian-backed rebels remain in control of parts of southeastern Ukraine.

Ukraine also refuses to recognize Russia’s annexation of the Crimean Peninsula. Russia invaded the territory in early 2014 and later incorporated it as a federal subject.

Most of the Crimea’s ethnic Russians and Russian speakers voted to join Russia in a referendum. But the native Muslim Tatars, many of whom were deported to Central Asia under the Soviet Union, were apprehensive. They are estimated to make up 12 percent of the population.

The peninsula is also still dependent on Ukraine for virtually all its electricity and water as well as 60 to 70 percent of its food.

Earlier this year, Russian media reported that the country was spending more than $800 million on a power cable to Crimea.

Russia is also paying some $4 billion for a new road and rail bridge across the Kerch Strait.

The Crimea currently has no overland connection to mainland Russia.

East-West tension

Russia invaded the peninsula last year when Ukraine was on the verge of signing an association agreement with the European Union that could be a step toward full membership of the 28-nation bloc.

It cut off coal and gas supplies at the time as well in an attempt to convince Ukraine — which only gained its independence from Russia in 1991 — to join a Moscow-led customs union instead.

The economic pressure and Russia’s subsequent use of force backfired. Ukraine signed the association treaty three months after Russia seized the Crimea. It is due to come into effect at the start of 2016.