The White House on Friday appeared to downplay the possibility of changing U.S. policy on exporting natural gas to address the situation in Ukraine.
White House spokesman Josh Earnest told reporters on Air Force One that policy changes would not have an immediate effect and noted that stocks in Europe were above normal levels because of a mild winter.
Europe and Ukraine are key export markets for Russian natural gas.
Obama, Putin Find Little Common Ground on Ukraine
Earlier, U.S. President Barack Obama spoke by phone with Russian President Vladimir Putin, but the two leaders found little common ground. The White House says President Obama told Putin the presence of Russian forces in Ukraine's Crimean peninsula is a violation of Ukraine's sovereignty.
The Kremlin says Putin denounced Ukraine's new Western-backed government as "illegitimate" and said Russia cannot "ignore" calls for help from Ukraine's Russia-leaning east and south.
Putin's spokesman said Friday that despite "deep disagreement'' with the West over Ukraine, Moscow hopes some common ground can be found and a new Cold War will not begin, Russian news agencies reported.
"There still remains hope...that some points of agreement can be found as a result of dialogue - which our partners, thank God, have not yet rejected,'' state-run RIA quoted spokesman Dmitry Peskov as saying. "I believe that it [a new Cold War] has not started and I would like to believe it will not start,'' Peskov said.
According to the White House, President Obama, in his phone conversation with Putin, called for direct talks between Kyiv and Moscow that would be mediated by the international community. Obama called for all Russian forces to return to their bases and for international monitors to ensure the safety of Ukrainians, including ethnic Russians.
In Washington Thursday, the president authorized sanctions, including visa restrictions, against those found to have violated Ukraine's territorial integrity. The EU also imposed measures against Russia, suspending talks on visas and a new economic agreement.
On Capitol Hill, the U.S. House of Representatives voted to provide loan guarantees of $1 billion to Ukraine. That measure now goes to the U.S. Senate. The European Union is prepared to extend a $15 billion bailout to Kyiv if Ukraine can reach an agreement with the International Monetary Fund.
Some information for this report provided by Reuters