Despite six hours of talks, the U.S. and Russia found "no common vision" Friday over the crisis in Ukraine, where residents in the country's strategic Crimean region are holding a secession vote this weekend, the Associated Press reported.
Russian Foreign Minister Sergey Lavrov made the comment after meeting with U.S. Secretary of State John Kerry in London.
At the marathon talks, Lavrov made it clear that Russian President Vladimir Putin would not make any decision about what to do with Crimea - which is now under the control of Russian-backed forces - until after Sunday's vote. Kerry, however, said Washington and the international community won't recognize the outcome of the referendum.
Sunday's vote on Crimea - Ukraine's strategic Black Sea peninsula of 2 million people - is widely expected to back secession and, potentially, annexation with Russia, since the area already has a majority Russian population. The new government in Kiev believes the vote is illegal, but Moscow says it does not recognize the new government as legitimate since it forced out Ukraine's pro-Russian president.
The U.S. and EU say the Crimean vote violates Ukraine's constitution and international law. If Crimea votes to secede, the U.S. and European Union plan to slap sanctions as early as Monday on Russian officials and businesses accused of escalating the crisis and undermining Ukraine's new government.
Kerry said if Russia's parliament ratifies a Crimea referendum vote, it would be akin to a "backdoor annexation" of the region.
"That is a decision of enormous consequence with respect to the global community," he told reporters at a news conference after the talks. "It would be against international law and, frankly, fly in the face of every legitimate effort to try to reach out to Russia and others to say there is a different way to protect the interests of Crimeans, to protect Russia's interests and to respect the integrity of Ukraine and the sovereignty of Ukraine."
Lavrov reaffirmed that Russia will "respect the results of the referendum" in Crimea and said sanctions would harm relations.
"Our partners also realize that sanctions are counterproductive," he said.
European and U.S. leaders have repeatedly urged Moscow to pull back its troops in Crimea and stop encouraging local militias there who are hyping the vote as a choice between re-establishing generations of ties with Russia or returning to echoes of fascism from Ukraine's World War II era, when some residents cooperated with Nazi occupiers.
The showdown between Russia and the West has been cast as a struggle for the future of Ukraine, a country with a size and population similar to France. Much of western Ukraine favors ties with the 28-nation European Union, while many in eastern Ukraine have closer economic and traditional ties to Russia. Putin has worked for months to press Ukraine back into Russia's political and economic orbit.
Russia has sent thousands of troops to its long border with Ukraine, a move that U.S. officials have called an intimidation tactic cloaked as military exercises. The Russian drills announced Thursday included large artillery exercises involving 8,500 soldiers in the Rostov border region alone.
Kerry said Moscow must send a stronger signal that troops along the Ukrainian border are not there to mount a military incursion.
"All of us would like to see actions - not words - that support the notion that people (Russian troops) are moving in the opposite direction and in fact diminishing their presence," he said.
The Russian Foreign Ministry engaged in more sabre-rattling Friday by warning that it reserves the right to intervene in eastern Ukraine in defense of ethnic Russians who it claims are under threat. Lavrov, however, denied any plans to send troops into eastern Ukraine.
"Russia doesn't and can't have any plans to invade southeastern regions of Ukraine," he said.
The Russian Foreign Ministry said clashes overnight Thursday in the eastern city of Donetsk showed that Ukrainian authorities had lost control of the country and could not provide basic security.
The clashes broke out, however, when a hostile pro-Russian crowd confronted pro-government supporters. At least one person died and 29 were injured.
Ukraine responded by calling the Russian statement "impressive in its cynicism."
"(The Donetsk clashes had) a direct connection to deliberate, destructive actions of certain citizens of Russia and some Russian social organizations, representatives of which are present in our country to destabilize the situation and escalate tensions," Ukrainian Foreign Ministry spokesman Evgeny Perebiynis said, according to the Interfax news agency.
The U.N. assistant secretary-general for human rights, Ivan Simonovic, told reporters Friday in Kiev there was "no sign of human rights violations of such a proportion, of such widespread intensity that would require any military measures."
Western officials have asked Russia to start diplomatic talks with Kiev to de-escalate tensions but Russia says that government illegally drove Ukraine's pro-Russian president from power.
British Prime Minister David Cameron underlined the threat of sanctions.
"We want to see Ukrainians and the Russians talking to each other. And if they don't, then there are going to have to be consequences," Cameron told Kerry in a separate meeting Friday in London.
Kerry arrived in London with plans to make clear to Lavrov about the stakes that Russia faces. The U.S. wants Russia to accept something short of a full annexation of Crimea - but Kerry has not said what that might entail. He told senators in Washington that should the Crimea vote take place and no resolution is reached, "there will be a very serious series of steps on Monday in Europe and here."
Obama has imposed limited sanctions against unidentified Russian officials thought by the U.S. to be directly involved in destabilizing Ukraine. But Congress on Thursday put off a vote until after March 24 that would have expanded those sanctions, as well as approve $1 billion in loan guarantees to Ukraine.