AMSTERDAM (Reuters) - U.S. President Barack Obama said on Tuesday that Russia's annexation of Crimea was not a "done deal" as it has not been recognized by the international community.
He added that Washington was concerned about the possibility of further Russian encroachment into Ukraine.
"It is up to Russia to act responsibly and show itself once again to be willing to abide by international norms and ... if it fails to do so, there will be some costs," he said at the end of a nuclear security summit in The Hague.
He said additional sanctions would hurt Russia, but also the economies of other countries.
(Reporting By Anthony Deutsch)