Russia will respect the result of Sunday's referendum in Crimea, Russian Foreign Minister Sergey Lavrov told reporters Friday after his meeting with U.S. Secretary of State John Kerry.
Asked if Kerry threatened sanctions against Russia during their meeting, Lavrov told reporters that Kerry "did not put forward any threats against Russia."
Still, Lavrov said, Russia is aware that Washington and European governments are considering sanctions against Russia because of the Ukraine crisis.
"I assure you that our partners understand that sanctions are counter-productive ... and (they) will not facilitate mutual interests," he said.
Describing his meeting Kerry, Lavrov said he expressed concern that necessary measures have not been taken to secure stability in Ukraine, and that measures have not been taken to stop what he called unlawful activities of radicals, including armed violence, in that country.
Lavrov also condemned recent violence in Donetsk, Ukraine. He said Russia has no plans to get involved there, but added that the rights of ethnic Russians have to be respected.
The outcome of their last-ditch talks was eagerly anticipated as a contentious referendum on the future of Ukraine's Crimean region looms.
The two men met four times last week in Europe and have been in daily phone contact since. But they have failed to reach common ground on how to solve the crisis over Crimea.
They met again at the residence of the U.S. ambassador to London as the clock ticks down on efforts to find a diplomatic solution.
Crimea's pro-Russian government has scheduled a referendum Sunday in which residents of the Crimean Peninsula will vote whether to secede from Ukraine and join Russia or to choose effective independence.
Ukraine's interim government in Kiev, as well as U.S. and European leaders, has warned that the vote is illegitimate.
President Barack Obama said Europe and the United States "stand united" on Ukrainian sovereignty and subsequent consequences if that sovereignty is violated.
"We continue to hope there's a diplomatic solution to be found" in Ukraine, Obama told reporters Friday during a meeting with Ireland's prime minister. He made those comments before the Kerry-Lavrov meeting concluded.
Before the talks with Lavrov, Kerry met with UK Prime Minister David Cameron and Foreign Secretary William Hague at 10 Downing St.
"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 said.
Both Europe and the United States have warned Russia of potential sanctions if it continues its actions in Ukraine.
"Hopefully, we all hope that we don't get pushed into a place where we have to do all those things. But we'll see what happens," Kerry said.
'Costs' for Russia
A senior State Department official said ahead of Kerry's arrival that "there will be costs" for Russia if the Crimea referendum goes ahead.
"Our analysis is that Russia has encouraged, aided and abetted this referendum process from day one and financed it," the official said.
The United States has urged Russia to de-escalate the situation by talking to the government in Kiev, pulling back Russian forces in Crimea to their barracks and allowing in international observers to ensure the rights of all ethnic groups are maintained.
Russia has said that it has the right to intervene in Ukraine to protect ethnic Russians from "fascists" and nationalists. It denies that its forces are militarily involved in Crimea, despite evidence to the contrary.
Ukraine's interim Prime Minister Arseniy Yatsenyuk blasted what he called Russia's illegal "military aggression" against his nation as he addressed the U.N. Security Council in New York on Thursday
But he also insisted that a peaceful resolution that ends with Kiev and Moscow becoming "real partners" is still possible and that he is "convinced that Russians do not want war."
Russian military drills
Yatsenyuk's remarks come as about 8,500 Russian troops staged snap military exercises not far from his nation's eastern border.
The United States is "very concerned" about the drill and will be asking Lavrov what is meant by it, the senior State Department official said Thursday.
"This is the second time inside of a month that Russia has chosen to mass large amounts of force on short notice without much transparency around the eastern borders of Ukraine," the official said.
Vladislav Seleznev, a spokesman for the Ukrainian Ministry of Defense in Crimea, told CNN that 14 Uragan multiple rocket launch systems were seen being moved into Crimea's interior Friday, along with a convoy of Russian military vehicles.
An earlier report that Russian S-300 missiles had been seen was mistaken, he said. The Defense Ministry has no more information on where the convoy may be now, he said.
A CNN team in Crimea passed six long-range artillery guns in a convoy on the road from Dzhankoy to Chongar. The first vehicle had Russian license plates and the rest no plates.
six Russian jet fighters were moved to Bobruisk airfield in Belarus on Thursday, Russian state news agency RIA Novosti cited the Belarussian Defense Ministry as saying Friday.
The move is part of Belarus' offer to Russia to participate in joint military drills, the news agency reported. Belarus, a former Soviet republic, borders Russia and northern Ukraine.
Tensions spill into violence
Ukraine has been simmering since November, when protesters angry at the government -- in part for its president's move toward Russia and away from the European Union -- began hitting the streets. In February, after deadly clashes between security forces and demonstrators, President Viktor Yanukovych was ousted.
Rising tensions have centered on Crimea, an ethnic Russian-majority peninsula in the country's southeast where local officials have declared their allegiance to Russia and armed men have blockaded Ukrainian military sites.
Tensions also have spilled over into other parts of eastern Ukraine, such as Donetsk, where the regional health authority said a 22-year-old man was stabbed to death and at least 10 others were injured in clashes Thursday between pro-Ukrainian and pro-Russian protesters.
Russia's Foreign Ministry condemned the Donetsk violence, saying "right-wing radical groups" had attacked a peaceful demonstration against the interim government in Kiev.
"The authorities in Kiev are not controlling the situation in the country," a statement on its website said. "Russia is aware of its responsibility for the lives of its compatriots and citizens in Ukraine and retains the right to defend people."
But Ukraine's Foreign Ministry pointed the finger elsewhere. The violence was "a planned provocation that has direct correlation to the destructive actions of certain Russian Federation citizens and social organizations, coming to Ukraine in order to escalate the tensions," spokesman Evhan Perebiynis said at a Foreign Ministry briefing.
A court in Donetsk was considering a request Friday by the Donetsk City Council to ban protests over the weekend.
Russia slams Western 'interference'
Although the bloodshed has been limited, fears are growing that the crisis could turn into a full-scale military conflict.
Speaking after Yatsenyuk at the United Nations, Russian U.N. Ambassador Vitaly Churkin accused the West of having "fanned the flames of unrest" in Ukraine.
Since Yanukovych's "illegal" ouster, Ukraine's pro-Western government has exacerbated the crisis by clamping down on opposition and effectively "splitting this country (into) two parts," Churkin said.
As to Sunday's referendum, the ambassador said citizens there deserve the same right to self-determination as anyone. "Why should the Crimeans be the exception?" he asked.
As the war of words continued, Russian state media reported Friday that coordinated cyberattacks by hackers had disrupted government websites including those of the Kremlin and Russia's central bank. The websites appeared to be working normally again by Friday afternoon, RIA Novosti said.
Western officials warn Moscow
Western officials, meanwhile, warned Thursday that Russia will face significant consequences unless it changes course in Crimea, with Obama pledging to "stand with Ukraine."
In a speech to the German parliament, German Chancellor Angela Merkel said that Sunday's secession referendum was unconstitutional and that Russia's presence in the Black Sea peninsula violates Ukraine's territorial integrity. She warned Putin that his actions would lead to "catastrophe" for Ukraine.
"It would also change Russia economically and politically," she said.
In a phone call, French President Francois Hollande told Putin the referendum "has no legal basis," urging the Russian leader to "do everything to prevent the annexation of Crimea to Russia."
At a Senate committee hearing in Washington, Kerry predicted that the upcoming vote would favor Crimea rejoining Russia.
But he warned that, absent movement by Russia toward negotiating with Ukraine on the crisis, "there will be a very serious series of steps Monday in Europe and here."
The U.S. Senate is weighing legislation that could impose economic penalties on Russians involved in the intervention in Crimea. The measure would represent some of the toughest sanctions on Moscow since the end of the Cold War.
Last week, Obama issued an executive order slapping visa bans on Russian and Ukrainian officials involved in the intervention and laying the groundwork for financial sanctions against those responsible for the crisis.
The European Union has been divided over how quick and severe the sanctions should be, but European officials say they are considering travel bans, asset freezes and possibly sanctions against Russian companies and banks if Russian aggression continues.
A way out for Putin?
American historian Timothy Snyder, author of "Bloodlands: Europe Between Hitler and Stalin," said Putin has put himself in a difficult position, but there may still be an exit route.
"All of the official claims
that have been made by Russia have been met. Their bases are secure, Russian speakers are not under any threat, so there is in theory a way out for the Russians, since none of their reasons for intervention are actually true," he said.
But the blitz by the Russian "propaganda machine" may make it harder for Putin to scale back Russia's activities, he said, with many Russians believing the claims made of a fascist threat to Russian speakers in Ukraine.
"Putin has now put himself in a very exposed position, has staked his leadership and his popularity on some kind of victory here, so it seems that he has unleashed a process that is now beyond his control," he said.
Alexander Nekrassov, a former Kremlin adviser, offered a very different take on events. He told CNN's Christiane Amanpour that Putin had no choice but to intervene after what Nekrassov said was "basically an armed coup" in Kiev.
"The situation got out of control," he said. "There was no way Russia could afford to have a sort of a semi-simmering civil war in Ukraine. The situation in Crimea -- there would have been a bloodbath there; there would've been -- there was no choice for Putin, and he had to act."
Nekrassov said there was no question that the referendum would go ahead Sunday, despite the efforts of U.S. and EU leaders to halt it.