Continued from page 1

Ukrainian Prime Minister Arseniy Yatsenyuk appealed for outside help and said Crimea remained part of his country. “Any attempt of Russia to grab Crimea will have no success at all. Give us some time,” he said at a news conference with British Foreign Secretary William Hague.

European foreign ministers held an emergency meeting on a joint response to Russia’s military push.

Mr. Hague, like other Western diplomats, ruled out military action. “The U.K. is not discussing military options,” he said. “Our concentration is on diplomatic and economic pressure.”

After a 90-minute phone call between Mr. Obama and Mr. Putin over the weekend yielded no apparent results, the president said he understood the historic ties between Russia and Ukraine. But Mr. Obama said Ukrainians must determine their own future.

“The strong condemnation … from countries around the world indicates the degree to which Russia is on the wrong side of history,” Mr. Obama said.

The president said Russia has a choice of two paths. “Obviously, the facts on the ground in Crimea are deeply troubling, and Russia has a large army that borders Ukraine,” Mr. Obama said. “Now is the time for them to consider whether they can serve their interests in a way that resorts to diplomacy as opposed to force.”

The administration, along with the other members of the G-8 besides Russia, has halted preparations for the group’s annual June summit, this year scheduled for Sochi, Russia.

Mr. Obama said he is looking at a range of other steps that “will have a negative impact on Russia’s economy and status in the world.”

Lawmakers in both parties expressed interest in an aid package for Ukraine.

Sen. Robert P. Casey Jr., Pennsylvania Democrat, suggested loan guarantees and other economic assistance. House Majority Leader Eric Cantor, Virginia Republican, said he has directed House committee chairmen to develop a package of loan guarantees rapidly to show that “the United States will not stand idly by in the face of such aggression.”

Mr. Obama said such aid should be “the first order of business” when Congress resumes work Tuesday. “At this stage, there should be unanimity among Democrats and Republicans that when it comes to preserving the principle that no country has the right to send in troops to another country unprovoked,” the president said. “We should be able to come up with a unified position that stands outside of partisan politics.”

The threat of sanctions may not be enough to change Mr. Putin’s mind, analysts said.

Economic and diplomatic measures “are about all we can do right now,” said Steven Bucci, director of the Douglas and Sarah Allison Center for Foreign and National Security Policy at the Heritage Foundation.

“Is it good enough? I’m not terribly optimistic,” he said.

A powerful member of the Senate Armed Services Committee said Mr. Obama’s mismanagement of the defense budget is the reason that the U.S. has limited options for assisting Ukraine.

Story Continues →