Last Updated Mar 14, 2014 1:45 PM EDT
LONDON -- Russian Foreign Minister Sergey Lavrov said Friday that differences remain between Moscow and the U.S. following negotiations in London aimed at ending the crisis in Ukraine, whose strategic Crimea region is voting this weekend on whether to secede.
After several hours of talks with U.S. Secretary of State John Kerry, Lavrov confirmed there was "no common vision" between the two nations - although he described the dialogue as "useful."
Kerry later told reporters that the United States and the international community wouldn't recognize the results of Sunday's vote on Crimea - Ukraine's strategic Black Sea peninsula of 2 million people.
Kerry said Friday he had put forward several ideas on how to respect Ukraine's sovereignty and address Russian concerns in the talks in London, but that Lavrov made clear that Russian President Vladimir Putin would not take any decisions until after Sunday's vote.
The referendum is widely expected to back secession and, potentially, annexation with Russia. The new government in Kiev believes the vote is illegal, but Moscow says it does not recognize the new government as legitimate.
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.
Lavrov on Friday 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.
While 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 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 that there was "no sign of human rights violations of such a proportion, of such widespread intensity that would require any military measures."
Russia has also 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.
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.
U.K. Foreign Secretary William Hague said while it was "not too late" for the Crimea referendum to be canceled, it was important to be "realistic" about the prospects.
"The fact that so far Russia has not taken any actual action to de-escalate the tensions makes this a formidably difficult task today," Hague said.
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."
President Obama has imposed visa restrictions 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 and International Monetary Fund revisions to help Kiev.