Russian President Vladimir Putin called U.S. President Barack Obama Friday to discuss a U.S. proposal for resolving the crisis in Ukraine.
The White House says Mr. Obama suggested that Mr. Putin offer a written response to the proposed diplomatic solution presented to Foreign Minister Sergei Lavrov by Secretary of State John Kerry earlier in the week.
A White House statement about the call did not give details of the proposal Kerry gave Lavrov, but the United States has been pressing Russia to pull back its troops to their Crimean bases and allow international monitors to go into Crimea to assure that the ethnic Russian minority there is safe.
President Obama says the Ukrainian government continues to take a "restrained and de-escalatory" approach to the crisis and urged Russia to support this process and avoid further provocations.
Lavrov and Kerry are expected to meet again in the coming days to discuss the next steps.
Earlier, in an interview with CBS, Mr. Obama said Russia's military moves near the Ukrainian border may be an effort to intimidate Ukraine.
Meanwhile, United Nations Secretary-General Ban Ki-moon said Mr. Putin has assured him that Russia has no intention of making additional moves into Ukrainian territory.
In comments to reporters at the U.N. Friday, Mr. Ban urged Russia and Ukraine to avoid "hasty actions" and immediately engage in direct and constructive dialogue to resolve their problems.
The head of Ukraine's national security council said Russia has close to 100,000 troops along Ukraine's borders in the north, south, and east. He said Russian forces are in full readiness to strike. Western experts believe the number of Russian forces near eastern and southern Ukraine is close to 30,000.
Also Friday, Russia described as "counterproductive" a U.N. resolution that refuses to recognize its annexation of the Crimean peninsula from Ukraine. Russia's Foreign Ministry said the U.N. General Assembly resolution will only complicate efforts to settle Ukraine's internal political crisis.
Crimea's majority Russian residents voted to break away from Ukraine and join Russia in a referendum earlier this month that Western powers deemed illegal.
Ousted Ukrainian president Viktor Yanukovych called Friday for referendums to determine the status of all Ukrainian regions. He said only a nationwide referendum and not an early presidential election can stabilize Ukraine and preserve its sovereignty and integrity.