(AFP/Getty Images)

President Obama warned Russian President Vladimir Putin by phone today that his country's intervention in the Crimean Peninsula is in violation of Ukraine's sovereignty and territorial integrity.

Obama urged Putin during an hour-long phone call this afternoon to embrace a diplomatic resolution "which addresses the interests of Russia, the people of Ukraine, and the international community," according to the White House.

"As a part of that resolution, the governments of Ukraine and Russia would hold direct talks, facilitated by the international community; international monitors could ensure that the rights of all Ukrainians are protected, including ethnic Russians; Russian forces would return to their bases; and the international community would work together to support the Ukrainian people as they prepare for elections in May," the White House said.

The phone call came just hours after Obama slapped new visa restrictions on Russians opposing the new Ukrainian government and cleared the way for financial sanctions against those contributing to the crisis.

Today's phone call was the leaders' second lengthy discussion since Russia intervened in the neighboring country. Obama and Putin had a tense 90-minute phone call last weekend.