Russia: Kiev Must Back Off Or Risk Civil War
Russia has warned Kiev that any use of force against pro-Kremlin militants in Ukraine's east could tip the country into civil war.
The warning came after pro-Russia activists seized state buildings in the eastern cities of Kharkiv, Lugansk and Donetsk.
They also declared independence and vowed to vote on joining Russia.
Kiev accused Russia of instigating the unrest and Washington warned the Kremlin to stop efforts to "destabilise Ukraine," accusations that Moscow brushed off.
The Russian foreign ministry said today it had information that Ukraine was sending internal security forces and volunteers from its National Guard to southeastern Ukraine including Donetsk.
It also alleged that Ukraine was deploying US private security operatives, dressed as Ukrainian special forces.
"We call for the immediate cessation of any military preparations, which are fraught with the risk of unleashing civil war," the Russian foreign ministry said in a statement.
Yesterday, US Secretary of State John Kerry threatened his Russian counterpart with "further costs" for Moscow should it make any moves to destabilise Ukraine.
The US State Department said Mr Kerry told Russian Foreign Minister Sergei Lavrov that Washington was watching events in eastern Ukraine with "great concern."
The warning came as Ukraine accused Russia of being behind the recent occupation of the government buildings by the pro-Kremlin activists.
Spokeswoman Jen Psaki said Mr Kerry urged Russia to "publicly disavow the activities of separatists, saboteurs and provocateurs" in the country.
She said the two also discussed holding direct talks in the next 10 days between Ukraine, Russia, the United States and the European Union.
Earlier White House spokesman Jay Carney publicly called on Russian President Vladimir Putin to "cease efforts to destabilise Ukraine."
Mr Carney said: "If Russia moves into eastern Ukraine, either overtly or covertly, this would be a very serious escalation."
He said there was strong evidence to suggest the protesters who seized the government offices were paid and not local residents, adding that the US was prepared to impose further sanctions.
The United States and European Union imposed sanctions on a Russian bank and officials in Mr Putin's inner circle in response to Moscow's annexation of the Crimean Peninsula
They are yet to be followed by any sanctions directly targeting the Russian economy.
On Monday pro-Russian separatists continued to occupy a provincial administration building in the eastern city of Donetsk.
Police said those inside the building are armed.