Obama and Putin (archive)
Obama and Putin (archive)Reuters

The United States has suspended all military engagements with Russia because of the crisis in Ukraine, including military exercises and port visits, as part of Washington's response to Moscow's seizure of Crimea, reports Reuters.

Monday’s announcement from the Pentagon came hours after President Barack Obama warned that the U.S. would look at a series of economic and diplomatic sanctions that would isolate Moscow.

"We call on Russia to de-escalate the crisis in Ukraine and for Russian forces in Crimea to return to their bases," Pentagon spokesman Rear Admiral John Kirby said in a statement quoted by Reuters.

Kirby said that although the Defense Department found "value" in military-to-military relations with Russia, "we have, in light of recent events in Ukraine, put on hold all military-to-military engagements."

Its suspension also applied to bilateral military meetings and planning conferences, he said.

Despite an international outcry over actions in Ukraine, Russia’s President Vladimir Putin has shown little sign of backing down, and Russia has built up armored vehicle presence near Crimea and staged military maneuvers in what appears to be a show of strength.

U.S. officials have dismissed the possibility of military options, which could further escalate the standoff, and the Pentagon appeared at pains to quash any speculation the U.S. armed forces were poised to get involved.

"Some media outlets are speculating on possible ship movements in the region. There has been no change to our military posture in Europe or the Mediterranean," Kirby said.

Also on Monday, the Senate’s Foreign Relations Committee said it was preparing legislation to provide support to Ukraine and consulting with the Obama administration on possible sanctions against individual Russians and Ukrainians cooperating with them.

On Saturday, Obama threatened Putin with political and economic isolation” over Russia’s military incursion in Ukraine.

The White House said Obama called on Putin to pull Russian troops back to their bases in Crimea and warned that continued violation of international law by Moscow would lead to further "political and economic isolation.”

Nevertheless, the president has been criticized by Republicans who say he is “all talk and no action” on Russia.

Sen. John McCain (R-AZ) took things further on Monday, telling the AIPAC conference that events in Ukraine are directly related to Obama's “feckless” policies.

While a military move is not an option for the U.S. at present, he opined, “the most powerful nation in the world should have many options – including economic actions." He added, with emotion, "This is the ultimate result of a feckless foreign policy where nobody believes in America's strength anymore!”