WASHINGTON: President Barack Obama said a deal Thursday to de-escalate tensions in Ukraine was a "glimmer of hope" but cautioned he could not be sure if Russia would live up to it.
Obama, in a careful response to the apparent breakthrough in Geneva, said he was coordinating with leaders in Europe about further sanctions against Moscow if progress was not evident within days.
"I don't think we can be sure of anything at this point. I think there is the possibility, the prospect, that the diplomacy may de-escalate the situation," Obama told reporters after four-way crisis talks in Switzerland between the US, Russia, Ukraine and the EU.
He called for an end to what he said was interference by Russia in eastern and southern Ukraine, where Washington has accused the Kremlin of backing pro-Moscow separatists who seized government buildings.
"We are not going to count on it until we see it," Obama warned.
In Geneva, the four parties agreed on steps to "restore security for all citizens," including a call to disband armed groups that have taken over buildings in Ukraine "illegally."
Obama made clear that if the West did not see action on those commitments, new sanctions would follow.
"We have put in place additional consequences that we can impose on the Russians if we do not see actual improvement of the situation."
Obama said he had discussed future measures with German Chancellor Angela Merkel and planned to speak to British Prime Minister David Cameron later.
"We're going to prepare additional responses should Russia fail to take a different course," said Obama.
"We've already had an impact on their economy. That is well-documented. It could get significantly worse."