President Barack Obama has said Vladimir Putin made a "strategic mistake" when he annexed Crimea, in a move that was "not so smart".
Those thinking his Russian counterpart was a "genius" had been proven wrong by Russia's economic crisis, he said.
US President wasspeaking in a wide-ranging interview with NPR,BBC informs.
International sanctions had made Russia's economy particularly vulnerable to changes in oil price, Obama added.
"The big advantage we have with Russia is we've got a dynamic, vital economy, and they don't," he said. "They rely on oil. We rely on oil and iPads and movies and you name it."
Crimea seceded from Ukraine and was annexed by Russia in March, folowing a local referendum on region's status, which was not recognized by international community and Kyiv.
The US and the EU, as well as other countries have imposed numerous economic sanctions, showing thier policy of non-recognition of Crimea's joining Russia.