Russian President Vladimir Putin telephoned U.S. counterpart Barack Obama to discuss the U.S. proposal for a "diplomatic resolution" to the crisis in the Ukraine, the White House said in a statement.

Obama, who was making a stopover in Saudi Arabia Friday after a trip to Europe, urged the Russian president Friday to withdraw his nation's troops from its border with Ukraine and not "take any steps to further violate (its neighbor's) territorial integrity and sovereignty."

Both leaders discussed the proposal that U.S. Secretary of State John Kerry presented to Russian Foreign Minister Sergey Lavrov during their meeting in The Hague earlier this week.

That proposal calls, among other things, for Russian troops to withdraw to their bases in the Crimean Peninsula and for Moscow to agree to talks with the new Ukrainian government under international mediation.

Obama suggested that Russia prepare a concrete written response and both presidents agreed that Kerry and Lavrov would meet again to discuss next steps.

"President Obama noted that the Ukrainian government continues to take a restrained and de-escalatory approach to the crisis and is moving ahead with constitutional reform and democratic elections," the White House said.

It urged Russia to support this process and "avoid further provocations, including the buildup of forces on its border with Ukraine."

Obama told Putin that his administration continues to support a diplomatic path to resolving the crisis in close consultation with Ukraine's government and is support of the Ukrainian people, the White House said.

Following the ouster in February of Ukrainian President Viktor Yanukovych, a Kremlin ally, Moscow sent troops to the strategic region of Crimea and subsequently annexed the peninsula after its mostly Russian-speaking population voted in a referendum to break off from the Ukraine and rejoin Russia.

Moscow said Yanukovych was removed from office on Feb. 22 by far-right Ukrainian nationalists and claimed it moved to protect ethnic Russians and Russian interests in Crimea in the wake of that development.

The crisis that led to Yanukovych's ouster erupted at the end of November, when the Ukrainian president backed away from plans to ink a pact with the European Union and instead signed a $15 billion financial-aid package with Russia.

The White House says it fears the buildup of Russian troops on the border with Ukraine, which holds presidential elections on May 25 that are widely expected to be won by a pro-West candidate, could lead to invasions of other Russian-speaking provinces.

Lavrov on Saturday promised that Russia would not invade mainland Ukraine but said that country should be made into a federation - as a means of protecting the interests of Ukraine's mostly Russian-speaking east and south - and pledge to stay out of NATO.