U.S. officials say China may be acting more out of self-interest than anything else as it watches Crimea and its majority ethnic Russian population prepare to vote on breaking away from Ukraine. China is grappling with its own ethnic minority groups in border regions that may feel stronger ties to neighboring countries.
White House spokesman Jay Carney wouldn't say whether Obama asked Xi for any specific actions, including support at the U.N., regarding the dispute between Russia and Ukraine.
"China obviously plays a very important role in the Security Council and does have an important relationship with Russia," he said.
Obama's call to Xi was part of a broader effort by the president to rally world leaders around the notion that Russia's incursion into Crimea violates international law. The Kremlin has so far shown little sign of backing down, and a referendum on whether to join Russia is scheduled in Crimea on Sunday.
Ahead of that vote, Obama will host Ukrainian Prime Minister Arseniy Yatsenyuk at the White House on Wednesday. The U.S. has promised Ukraine's new government $1 billion in loan guarantees, which would supplement a $15 billion aid pledge from the European Union.
European leaders have joined Obama in condemning Russia's push into Crimea, where 60 percent of the population is ethnic Russian.
Russia moved into Crimea after Ukraine's pro-Kremlin President Viktor Yanukovych fled the capital of Kiev. Yanukovych had faced three months of political protests after he scrapped plans to strengthen ties with Europe, a move Russia opposed.
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