The European Union and the United States are not poised to slap fresh sanctions on Russia despite a U.S. warning that Moscow had only 'hours" to act on disarming Ukraine separatists, Western diplomats said. U.S. Secretary of State John Kerry called on Russia to take steps to disarm separatists in Ukraine within "the next hours" as the European Union prepared to discuss deeper sanctions against Moscow at a Brussels summit. Washington and other Western powers have stepped up pressure on Russia to take concrete action to defuse the conflict in eastern Ukraine, where a truce between Russian-speaking rebels and government forces has appeared to crumble. "We are in full agreement that it is critical for Russia to show in the next hours, literally, that they're moving to help disarm the separatists, to encourage them to disarm, to call on them to lay down their weapons and to begin to become part of a legitimate process," Kerry told reporters in Paris after meeting French Foreign Minister Laurent Fabius. The U.S. State Department said it had new Russia sanctions "ready to go," but Kerry said the United States would prefer not to be in "sanctions mode" and wanted Russia to take action without pressure. Barring a surprise, Western diplomats said there is little chance of the European Union or United States imposing so-called "tier three" sanctions on Russia on Friday. Such steps could include barring Western purchases of debt from Russian state-owned enterprises, limiting technology transfers to Russian companies in the energy, financial services and high-tech sectors, and tightening up on defense trade. "The odds that the Europeans actually decide to implement tier three sanctions is very low," said a diplomat who spoke on condition of anonymity, saying the United States still seemed to prefer acting in concert with the EU rather than unilaterally. In Washington, the U.S. State Department said that Kerry did not mean to suggest that sanctions were in the offing on Friday. "The secretary wasn't outlining specific timing for additional sanctions but underscoring the need that this needs to happen quickly," spokeswoman Marie Harf told reporters. "We've been very clear that we remain prepared to impose additional sanctions, including sectoral, should circumstances warrant," she also said at her daily briefing. "We have in place the infrastructure to do this very quickly if we want to." U.S. officials have threatened additional sanctions against Russia in response to what they say is Moscow's increased support to Ukrainian separatists, including the provision of Russian tanks and other weaponry and allowing separatist fighters to cross into eastern Ukraine. Separatist rebellions erupted in eastern Ukraine in early April after street protests in Kiev toppled Moscow-backed leader Viktor Yanukovich, and Russia in turn annexed the Crimean peninsula. Eastern rebels have called for union with Russia. (Reuters)