U.S. Secretary of State John Kerry says the "window of opportunity" for Russia to change course in Ukraine is closing.
In a sharply worded statement to journalists in Washington on April 24, Kerry said that Russia has not taken "a single concrete step" to implement the agreement reached one week ago in Geneva to de-escalate the crisis in Ukraine.
"The Geneva agreement is not open to interpretation. It is not vague," Kerry said. "It is not subjective. It is not optional."
Kerry praised the government of Ukraine for its effort to implement the agreement "from Day 1." In contrast, he accused Russia of following a course of "deception, distraction, and destabilization."
He called Russia's actions a "full-throated effort" to undermine Ukraine's democratic processes and stability. Kerry said Moscow's decision on April 24 to move troops to the border with Ukraine was "threatening."
Kerry said that if Russia continues to undermine Ukraine, the consequences will be "grave" and "expensive."
Kerry's comments came amid a war of words between Western and Russian officials over the crisis in Ukraine.
In an interview on Russian television, Russian Ambassador to the United Nations Vitaly Churkin said the UN secretary-general should denounce Ukraine's "use of armed force against political opposition."
U.S. Defense Secretary Chuck Hagel, speaking during a visit to Mexico, said Russia's military manuevers on the border with Ukraine were "dangerously destabilizing and very provocative."
With reporting by ITAR-TASS