Ukraine-Russia crisis: US sanctions Crimean separatists and Chernomorneftegaz gas firm

One of the billionaires said being singled out was an "honour"

A unit of Ukrainian border guards line up before starting their patrol on the Russian border, in the village of Veseloye, in the Kharkiv region, on 4 April. (SERGEY BOBOK/AFP/Getty Images)

The United States imposed sanctions on high-profile Crimean separatists and the Chernomorneftegaz gas company based in the region on Friday, as part of the third round of sanctions in an attempt to ease tensions in what has become the worst diplomatic crisis between East and West since the Cold War.

US officials said the move aimed to make it impossible for Russian firm Gazprom to deal with Chernomorneftegaz.

On April 1, Russia's energy minister said Gazprom would pay for the construction of an undersea gas pipeline to Crimea and would take part in a tender on the privatization of the local energy company.

“We are saying to the world, with some teeth, you are not going to invest in Crimea with impunity,” warned a US official.

It also makes way for the possibility of a harder line ahead of talks among US, Russian, Ukrainian and EU officials in Geneva on Wednesday.

Leaders will discuss Russia’s annexation of Crimea last month, when Moscow sent troops into the region on 18 March – angering Western powers who claim Russia has massed forces on its border with the intent to seize more of the country.

As the prospect of the West invading Russia remains unlikely, its response has included economic sanctions, efforts to bolster the defenses of other European nations who fear Russia, and strong condemnation of Moscow's actions.

The news comes as pro-Russia activists continued their protests in eastern Ukraine. On Saturday the situation remained tense, as armed pro-Russia gunmen seized a police building in Slaviansk.

Additional reporting by Reuters