In unusually blunt language, Kerry said Thursday that unless Moscow takes immediate steps to de-escalate the situation, Washington will have no choice but to impose additional sanctions. He said It would be a "grave" and "expensive mistake." His comments come amid an increasingly bitter war of words over who is to blame for the crisis in Ukraine that is becoming steadily more violent.
The U.S. says Russia is fomenting unrest and separatist sentiment in eastern Ukraine following its annexation of the strategic Crimean Peninsula. Russia accuses the U.S. of encouraging a pro-Western government in Kiev to adopt anti-Russian policies.