WASHINGTON - The US and Russia continue to be at odds over the crisis in the Ukraine, with no sign of the two sides resolving their differences anytime soon.

US President Barack Obama on Wednesday once again warned Russia of more consequences against further "destabilizing" Ukraine, where pro-Russian militants seized government buildings in some eastern cities bordering Russia.

In an interview with CBS News, Obama said it was "absolutely clear" that Russia had violated Ukraine's sovereignty and territorial integrity by "annexing Crimea" last month and was continuing to do so by supporting "non-state militias" in eastern Ukraine.

Ukraine crisis

Moscow has, however, rejected accusations that Russia was destabilizing Ukraine. In a telephone conversation with Obama on Monday, Russian President Vladimir Putin urged the United States to use its influence to prevent bloodshed in Ukraine.

Washington and Moscow began to butt heads after Russia deployed troops to Crimea a few weeks back, with the US blasting the move as contrary to international law and imposing sanctions. Russia defended the move as an effort to protect ethnic Russians in the region.

Amid the sabre rattling, a Russian SU-24 fighter plane reportedly buzzed closely by the USS Donald Cook in the western Black Sea last Saturday, leading to fears that this could trigger military response from the US and its NATO allies in Europe.

But some experts said it was only a warning from Moscow to the US to back off from Russia regarding the Ukraine crisis. The Russian plane was unarmed, which suggested Russia does not want to escalate the row with the US too much.

"The incident with the Russian jet was intended to send a diplomatic message rather than signal hostile military intent. The fact that the jet was unarmed shows that Moscow wanted to limit the risk of escalation," David Clark, chairman of the Russia Foundation, told Xinhua. "The message it wanted to convey is that the Black Sea is part of Russia's sphere of influence and the US should keep out."

The incident has sparked much discussion among experts, geopolitical observers and pundits over whether Moscow now views Washington as weak.

"Russian policy makers see the US as strong, but not as strong as it used to be and no longer focused on Europe as its main strategic priority following Obama's Asian pivot. Moscow is testing US and European responses to gauge their willingness to support Ukraine and challenge Russian behavior before deciding what to do next," Clark said.

US-RUSSIA MILITARY CONFLICT UNLIKELY

A full-on military conflict between the two powers is unlikely.

"In a real military confrontation with the US involving the full mobilization of military forces, Russia would stand little chance," Clark said.

Moreover, there are doubts about Russia's capacity to sustain military operations, even in neighboring countries, he said.

The war with Georgia in 2008 exposed significant deficiencies in the equipment and organization of the Russian armed forces, so much so that many analysts believe Moscow suspended military operations sooner than it wanted to, Clark said.

That prompted Vladimir Putin to begin a military modernization program. Opinions differ on how successful that has been. Crimea was an easy conquest with an acquiescent local population. Eastern Ukraine would pose a more challenging test of Russia's current military capabilities, he said.

In any sense, a direct war between the US and Russia is unimaginable as they are the top two nuclear powers in the world.

So far the Obama administration has ruled out of military intervention in the Ukrainian crisis and repeatedly called for a diplomatic solution, as it faces hefty military budgetary cuts and a public weary of war after more than a decade of military involvements in Iraq and Afghanistan.

Obama told CBS News that Russia was not seeking "military confrontation" with the US despite the Ukrainian crisis. "They're not interested in military confrontation with us, we don't need a war," he said.

Meanwhile, US Secretary of State John Kerry left on Wednesday for Geneva for a Thursday meeting over the Ukrainian crisis with the European Union, Russia and Ukraine, in the latest attempt to de-escalate the tensions and seek a political solution.