A day after an international deal in Geneva to defuse the East-West crisis in Ukraine, pro-Russian separatists vowed not to end their occupation of public buildings and Washington threatened further sanctions on Moscow if the stalemate continued.

Leaders of gunmen who have taken over city halls and other sites in and around Donetsk this month in pursuit of demands for a Crimea-style referendum on union with Russia rejected the agreement struck in Geneva by Ukraine, Russia, the United States and European Union and demanded on Friday that the leaders of the Kiev uprising must first quit their own government offices.

Moscow renewed its insistence that it has no control over the "little green men" who, as before Russia annexed Crimea last month, appeared in combat gear and with automatic weapons to seize public buildings — a denial that Western allies of those who overthrew the pro-Russian president in Kiev do not accept.