Speaking to reporters in Kyiv, US Secretary of State John Kerry called on Russia to de-escalate tensions and to seek the correct legal remedies to pursue any concerns it has for the safety of ethnic Russians in Ukraine.

"The United States of America would prefer to see this de-escalated, we would prefer to see this managed through the structures of legal institutions ... in order to be able to deal with this kind of crisis," Kerry said, adding that Washington would stand by "the Ukrainian people."

He reprimanded Russia for sending in troops on the pretense of protecting ethnic Russians in the southern peninsula of Crimea - despite the lack of credible evidence for any request for help - calling it behavior unbefitting of the 21st century.

"This is the 21st century, and we should not see nations step backwards to behave in 19th- or 20th-century fashion. There are ways to solve these differences. Great nations choose to do this appropriately," Kerry said. "It is not appropriate to invade a country and at the end of a barrel of gun, dictate what you want to achieve."

Speaking to DW TV's Journal, the economics minister in Ukraine's interim government, Pavlo Sheremeta, said Kyiv was appreciative of Kerry's "timely" visit.

"He brought appropriate words for the country which is torn... wounded at the moment," Sheremeta said. "He paid his respects to the victims of Maidan, which was well appreciated here."

Kerry questions Russian rationale

Kerry also said that President Vladimir Putin had defended Russian military actions with information that was not true. Russia has accused Ukraine's interim government of failing to implement the February 21 peace deal. It has also alleged that the victors of the protest movement have taken control of the transitional government in Kyiv and are now seeking to destabilize Crimea.

"Not a single piece of credible evidence supports any of these claims," Kerry said.

Kerry pointed instead to Russia's backing of ousted Ukrainian President Viktor Yanukovych, who "broke his obligation to sign the agreement and ... abandoned his people and eventually his country." He also recounted the overwhelming approval of the current government, which includes members of Yanukovych's party. Kerry dismissed claims of attacks on ethnic Russians and reports of continued unrest in Kyiv as untrue.

Kerry said the United States did not seek military engagement with Russia. However, he said, the US would isolate Russia "politically, diplomatically and economically" if the country did not reverse its current course of action.

When asked about working together with Germany, Kerry said he was certain that the countries "would stand united." Both German Chancellor Angela Merkel and Foreign Minister Frank-Walter Steinmeier have played important roles in peaceful relations with Kyiv and Moscow in recent weeks.

Obama: Russia not 'fooling anybody'

US President Barack Obama also criticized Putin for denying the deployment of troops in Crimea, while speaking to reporters during a visit to a school in the Washington, DC, area.

"President Putin seems to have a different set of lawyers, maybe a different set of interpretations. But I do not think that is fooling anybody," Obama said. He said the military move was in violation of international law.

The US president added that Moscow still had time to change its stance and help international leaders stabilize Ukraine.

Putin denies sending troops to Crimea

Earlier on Tuesday, Russian President Vladimir Putin held a press conference in Moscow, where he gave his first public comments since Ukraine's interim leaders accused him of sending an estimated 16,000 troops to the Crimean peninsula.

Putin denied Russian operations in Ukrainian territory, saying only that "local forces of self-defense" have surrounded military bases. However, Putin said Moscow reserve the right to use all means to protect Russians in Ukraine.

Asked if Russian forces took part in operations in Crimea, he said: "No, they did not participate."

"There are a lot of uniforms that look similar," he added.

He also criticized international leaders for threatening sanctions on Russia's natural gas, uranium and coal industries.

So far, the United States has suspended plans to attend this summer's G8 summit in Sochi, military cooperation with Russia and bilateral economic dialogue.

kms/msh (AFP, Reuters)