WASHINGTON, March 6 -- U.S. President Barack Obama proposed a diplomatic resolution once again on Thursday to the ongoing crisis in Ukraine in his phone talks with Russian President Vladimir Putin.

In their hour-long conversation, Obama told the Russian leader that Russia's actions in Crimea, an autonomous republic in southern Ukraine, "are in violation of Ukraine's sovereignty and territorial integrity, which has led us to take several steps in response, in coordination with our European partners," the White House said.

The Obama administration announced visa bans and assets freeze Thursday against those Russians and Ukrainians involved in what it called Russia's takeover of Crimea, following suspension of trade and investment talks and military-to-military engagement with Russia.

"President Obama indicated that there is a way to resolve the situation diplomatically, which addresses the interests of Russia, the people of Ukraine, and the international community," the White House said in a readout of the talks, the second this week.

It said Obama's suggestions included direct talks between the governments of Ukraine and Russia; the deployment of international monitors to ensure the rights of all Ukrainians are protected, including ethnic Russians; the return of Russian forces to their bases in Crimea; and international support for presidential elections in Ukraine in May.

Obama also said U.S. Secretary of State John Kerry would continue discussions with his Russian counterpart Sergei Lavrov, though the pair had reached no agreement following their talks in Paris and Rome on Wednesday and Thursday.

Russia did not recognize Ukraine's new government put in place after pro-Russian President Viktor Yanukovych was ousted on Feb. 22, and called the events in the neighboring country a coup.