U.S. Secretary of State John Kerry has issued a statement in which he criticized the Russian authorities for the escalation of the situation in the east of Ukraine.

Kerry accused Moscow of having done nothing to de-escalate the situation in the region a week since the signing of the agreements in Geneva.

"Instead, in plain sight, Russia continues to fund, coordinate, and fuel a heavily armed separatist movement in Donetsk," Kerry said.

"And in the weeks since this agreement, we have seen even more violence visited upon Ukrainians. Right after we left Geneva, separatists seized TV and radio stations that broadcast in the Ukrainian language. The mayor of Sloviansk was kidnapped the very day after the parties committed to end the violence and intimidations. Two days ago, one journalist was kidnapped and another went missing, bringing the total number of kidnapped journalists into the double digits. That same day, two dead bodies were found near Sloviansk. One of them was a city councilmember who had been knocked unconscious and thrown in a river with a weighted backpack strapped to him.

In his words, only one side, one country, is keeping its word: "From day one, the Government of Ukraine started making good on its commitments – from day one. From day one, Prime Minister Yatseniuk has kept his word. He immediately agreed to help vacate buildings. He suspended Ukraine's counterterrorism initiative over Easter, choosing de-escalation, despite Ukraine's legitimate, fundamental right to defend its own territory and its own people. From day one, the Ukrainian Government sent senior officials to work with the OSCE, in keeping with the agreement, to send them to work in regions where Russia had voiced its most urgent concerns about the security of Russian speakers and ethnic Russians… He directly addressed the concerns expressed by the Russians, and he did so on day one."

In this regard, he warned that if Moscow does not change its position on Ukraine, then the United States will be ready to impose more sanctions against Russia.

"Let me be clear: If Russia continues in this direction, it will not just be a grave mistake, it will be an expensive mistake," Kerry said adding that they were "ready to act."