Russia threatened military action against the Ukranian government on Monday as pro-Russian separatists, allegedly backed by Russian Special Forces, strengthen their grip in the eastern part of the country.

Officials from the U.S. and European Union responded by saying that Russia is fully responsible for the breakdown in eastern Ukraine and would impose new sanctions if pro-Russian separatists did not cease actions.

According to a State Department spokesperson, Secretary of State John Kerry told Russian Foreign Minister Sergei Lavrov that a negotiated international peace agreement could only be implemented if Russia publicly called on separatists to "vacate illegal buildings and checkpoints."

Read more about the Ukranian crisis at Reuters, Washington Post, and The Australian.

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