President Obama on Tuesday dismissed Russian President Vladimir Putin’s charges that ethnic Russians are being threatened in Crimea as part of what Putin called a “coup” last week in Ukraine.

“Mr. Putin can throw a lot of words out there,” but “facts on the ground” tell a different story, Obama said Tuesday following a Putin news conference at his country residence west of Moscow.

Citing widespread international support for Ukraine’s new government, and agreement that Russia is violating international law by deploying troops throughout the Crimean autonomous region, Obama said that “President Putin seems to have a different set of lawyers, making a different set of interpretations.”

“I don’t think that’s fooling anybody,” Obama said.

He called on Putin to open talks with the Ukrainian government in Kiev and to allow international monitors to examine “if there is any evidence out there . . . that Russian speakers, Russian nationals are being threatened,” in Crimea or elsewhere in Ukraine.

As tensions rise between Russia and Ukraine, what can President Obama do? The Post's Scott Wilson and Karen DeYoung weigh in. (Jeff Simon/The Washington Post)

Obama appeared to be trying to strike a balance between escalating Western threats and appeals to the Russians to come to their senses. “There have been some reports that President Putin is pausing for a moment and reflecting on what’s happening,” he said without elaboration.

Beyond Ukraine, the sudden and rapidly worsening confrontation with Russia there puts in question U.S.-Russian diplomatic partnerships on a range of other issues, including the eradication of Syria’s chemical weapons and a stalled effort to mediate peace talks in the Syrian civil war; nuclear talks with Iran and over North Korea; and Russian assistance in withdrawing U.S. forces from Afghanistan.

Already, the administration has canceled U.S. participation in planning for a meeting of the Group of Eight leading industrialized countries scheduled to be held in June in Sochi, Russia, and the Pentagon has announced it is putting all military exchanges and joint exercises with Russia on hold. Treasury and State Department officials are examining specific sanctions against individual Russians deemed responsible for the Crimea crackdown and coordinating possible economic sanctions with Europe.

Although Secretary of State John F. Kerry was due to meet Russian Foreign Minister Sergei Lavrov later this week in Europe, diplomats said that meeting is now uncertain.

As Obama spoke, during an appearance to discuss his budget at Powell Elementary School in the District, Kerry delivered the same message during a visit to Kiev, where he announced U.S. assistance of $1 billion in loan guarantees to help the Ukrainian government.

Using somewhat sharper language than the president, Kerry condemned what he called Russia’s “falsehoods, intimidation and provocations” in Ukraine and said Moscow appears to be seeking a “pretext for being able to invade further.”

In addition to pledging financial and technical help for Kiev’s caretaker government, Kerry warmly endorsed the interim leaders as statesmen. Washington will continue to support a democratic Ukraine with money and diplomatic muscle, he said, but he made no mention of a miliary show of force to counter Russia’s intervention in Ukraine’s Crimean Peninsula.

“There is nothing strong about what Russia is doing,” Kerry said during a news conference following several hours of meetings with Western-oriented former opposition figures, who are now part of a temporary government and are facing a military standoff with Moscow.

“It’s time to set the record straight,” Kerry said.

“I think it’s is clear that Russia has been working hard to create a pretext for being able to invade further,” Kerry said with obvious frustration and anger. He dismissed Moscow’s claim that Russian speakers are under threat in Ukraine since the fall of the Moscow-backed government of President Viktor Yanukovych last month.

While Russia has leveled charges of violence and threats against ethnic Russians, threats against Russian bases and the rise of “ultranationalists” and “Nazis” on the streets of Ukraine, Kerry said none of it was true.

“Not a single piece of credible evidence supports any one of these claims,” Kerry said. “None.”

Putin denied charges by Western governments and the Kiev leadership that Russia had sent additional troops into Crimea to supplement about 11,000 permanently stationed there under long-standing basing agreements with a series of Ukraine governments.

In their comments Tuesday, both Obama and Kerry avoided specific charges about a new influx of Russian troops. Obama spoke of “still seeing soldiers out of their barracks in Crimea.”

Like Kerry, Obama rejected any “suggestion somehow that the Russian actions have been clever strategically,” as Moscow seeks to preserve its political and economic influence over Ukraine.

“I actually think this has not been a sign of strength, but rather is a reflection that countries near Russia have deep concerns and suspicions about this kind of meddling and, if anything, it will push more countries further away from Russia.” He called on Putin to work with the international community to support Ukraine’s upcoming elections in May.

The United States and its allies in Western Europe have shown no desire to become involved in a military standoff with Russia over Ukraine. But Eastern European countries that joined NATO after the fall of the Soviet Union have been far less sanguine about the need to stand up forcefully to Russia, and a special alliance meeting, requested by Poland, was taking place Tuesday in Brussels to discuss their security concerns.

Kerry is the highest-level American official to come to the former Soviet republic since the ouster of Ukraine’s Russian-backed leadership 10 days ago.

New economic sanctions against Russia are coming in “days, not weeks,” a U.S. official traveling with Kerry said.

Putin has a way out, and he should take it, Kerry said, appealing to Russia to embrace diplomacy.

If Russia presses ahead with “aggression” in Crimea or elsewhere, the United States and other nations will move to further “isolate Russia politically, diplomatically and economically,” Kerry said.

“This is not something we are seeking to do,” Kerry said. “This is something Russia’s choices may force us to do.”

Kerry commended the new Ukrainian government for showing “restraint despite an invasion of the Ukrainian homeland.” He said Russia was “out of excuses” for its intervention in Crimea and was “hiding its hand behind falsehoods, intimidation and provocations.”

He called on the Russians to “de-escalate rather than expand their invasion.”

A senior U.S. lawmaker expected to help steer a Ukrainian aid package through Congress said Tuesday that the pledge of $1 billion in U.S. loan guarantees was “welcome news.”

“The time to act is now,” House Foreign Affairs Committee Chairman Edward R. Royce (R-Calif.) said in a statement shortly after Kerry announced plans for the aid package. “We must place crippling sanctions on Russian high-ranking officials, state owned banks and commercial enterprises, and key individuals behind the Russian intervention. Only by forcing [Russian President Vladimir] Putin to reverse aggression and by supporting Ukraine in this time of national crisis can we hope to restore peace in the region.”

In Kiev, Kerry visited a memorial to some of the scores of civilians killed when government forces opened fire last month on street protests against Yanukovych.

Yanukovych fled to Russia more than a week ago and maintains he is still Ukraine’s legitimate leader. Putin agreed Tuesday, justifying Russian intervention in Crimea as a legal response to a request from Yanukovych as president.

Kerry has argued that Yanukovych lost his claim on power when he fled, and he said the new government deserves solid Western backing to begin work and to recover stolen national assets.

Congress plans debate next week over approval of the $1 billion Kerry is offering Ukraine, an assistance package designed in part to help protect Ukraine from likely price increases for energy if Russian supplies are slashed.

During a tour of Kiev, Kerry walked along a muddy Institutska Street, the site of dozens of deaths from sniper or automatic weapons fire last month. Piles of soggy flowers, many snarled with barbed wire, lined the street. Remnants of barricades built of tires, packing crates, garden gates and a mattress remained.

Kerry spoke to groups of people, most of whom appeared to be supporters of the new government.

“We are helping you,” Kerry told one woman. “President Obama wants to help you. I want to help you.”

A few moments later, a group of people who identified themselves as Russians called out to Kerry, and he also told them that the United States wants to help.

“We are poor people,” a woman told Kerry in Russian, before Kerry moved down the street in a chaotic throng of security, cameras and bystanders. He placed a candle at a makeshift shrine erected to slain protesters, some of whose young faces looked out from sodden photographs.

The shrine is near the site of the heaviest gunfire on Feb. 20, the deadliest day of three months of demonstrations against Yanukovych. At least 98 people died during the protests — many of them along the route Kerry walked.

Roman Catholic, Ukrainian Orthodox and other clergy were there to greet Kerry on the street, invited by the U.S. Embassy in what organizers hoped would be a display of unity and calm. One of the Orthodox prelates was part of the Kiev patriarchate, another from the Moscow division of the church.

Later, Kerry met leaders of the interim government that took power when Yanukovych fled and that has pledged quick elections and a return to full democracy. The United States, however, is concerned by signs of at least mild recriminations against Russian speakers or those who identify with Moscow.

Walking into Ukraine’s parliament, Kerry passed a long table lined with photographs of those killed in the protests.

He met with acting President Oleksandr Turchynov, Prime Minister Arseniy Yatsenyuk and other officials who, until two weeks ago, were part of opposition protests calling for Yanukovych’s ouster.

Gearan reported from Kiev. Ed O’Keefe in Washington contributed to this report.