WASHINGTON - Unsuccessful with previous threats, the United States and its European allies stepped up their pressure on Russia to end its intervention in Ukraine on Monday by imposing the most comprehensive sanctions against Russian officials since the Cold War.
Acting in concert with Europe, the Obama administration froze the U.S. assets of seven Russian officials, including top advisers to President Vladimir Putin, for their support of Crimea's vote to secede from Ukraine, while similar sanctions were imposed on four Ukrainian officials for instigating Sunday's Crimean referendum.
Although the threat of sanctions has failed thus far to persuade Putin to drop support for Crimea's secession and potential entry into the Russian Federation - or to pull back from threatening military moves near Ukraine's south and east - President Barack Obama said failure to step back now would draw move severe consequences.
"If Russia continues to interfere in Ukraine, we stand ready to impose further sanctions," Obama declared at the White House shortly after the penalties were announced. He noted that Vice President Joe Biden would be traveling to Europe late Monday to reassure Eastern European leaders of America's commitment to them and that he himself would be going next week on a previously planned trip to make a similar point. Secretary of State John Kerry also is expected in Europe in the coming days.
"We'll continue to make clear to Russia that further provocations will achieve nothing except to further isolate Russia and diminish its place in the world," he said. "The international community will continue to stand together to oppose any violations of Ukrainian sovereignty and territorial integrity, and continued Russian military intervention in Ukraine will only deepen Russia's diplomatic isolation and exact a greater toll on the Russian economy."
But administration critics said Obama's actions were too little to convince Putin of anything.
"I think Vladimir Putin must be encouraged by the absolute timidity," said Sen. John McCain, R-Ariz., who had just returned from a weekend trip to Kiev.
"I don't know how it could have been weaker, besides doing nothing - seven people being sanctioned after naked aggression has taken place," he told MSNBC.
Shortly after Obama's comments, Putin recognized Crimea as a "sovereign and independent country."
Residents in Crimea, a strategic Black Sea peninsula, voted overwhelmingly Sunday in favor of the split, and Crimea's parliament declared the region an independent state on Monday. In Washington, Obama administration officials said there was evidence that some ballots for the referendum had arrived pre-marked in many cities and there were "massive anomalies" in the vote. The officials did not say what that evidence was.