The Russian Foreign Ministry has voiced concerns over the buildup of Ukrainian forces and US mercenaries in the southeastern part of the country, calling on Kiev to immediately cease military preparations which could lead to a civil war.

As parts of Ukraine push for greater autonomy – with Donetsk and Kharkov declaring independence on Monday – the self-imposed government in Kiev is reportedly dispatching additional forces in turbulent regions to avoid potential disobedience by local law enforcements.

“We are particularly concerned that the operation involves some 150 American mercenaries from a private company Greystone Ltd., dressed in the uniform of the [Ukrainian] special task police unit Sokol,” the Russian Foreign Ministry said in a statement. “Organizers and participants of such incitement are assuming a huge responsibility for threatening upon the rights, freedoms and lives of Ukrainian citizens as well as the stability of Ukraine.”

Ukraine's acting interior minister, Arsen Avakov, confirmed that additional police special forces units have arrived in southern and eastern parts of Ukraine from other regions.

“These special forces are ready to solve operational problems without the regard to local peculiarities,” Ukraine's Interior Ministry quoted Avakov as saying. “I urge all the hotheads now to defer from criticism and panic, and help the police keep the situation under control.”

According to the Russian Foreign Ministry, special forces backed by militants from the Right Sector are being tasked with suppressing protests in the southeastern regions of Ukraine, which for weeks have been calling for a referendums on the regions' statuses within Ukraine. Moscow called on the government in Kiev to refrain from actions that could spark a civil war in Ukraine.

“We urge [Kiev] to immediately stop all military preparations which could lead to a civil war,” the statement reads.

On Monday, a source in the Interior Ministry of Ukraine told Ria Novosti that three special forces units have been redeployed to the Donetsk and Lugansk regions to suppress anti-government protests. The source claims that they consist of Interior Forces units, the newly-formed National Guard, Right Sector radicals, and Blackwater (Greystone) mercenaries and Falcon units.

In a separate press release on Monday, the Russian Foreign Ministry said that it is “closely watching what happens in the eastern and southern regions of Ukraine, in particular in the Donetsk, Lugansk and Kharkov regions.”

Moscow noted that without “real constitutional reform in Ukraine,” the “federalization” of the country, and the implementation of Russian as a second official language, long-term stabilization of the crisis is unlikely.

The ministry said that is time to stop “putting the blame on Russia, accusing [Moscow] of all the troubles in today's Ukraine.”

Instead, Moscow urged Kiev to answer the legitimate questions that people in Ukraine have for the self-imposed government.

“Ukrainian people want to get a clear answer from Kiev to all their questions. It's time to listen to these legal claims,” the Foreign Ministry said, accusing the Ukrainian government of acting “irresponsibly.”

At the same time, the ministry confirmed the Kremlin's commitment to kickstart a national Ukrainian dialogue to stop the crisis. Russia is trying to propose the federalization of Ukraine, where regions would have broader powers of autonomy - including the right to promote regional language minority rights.

Meanwhile, the US hinted that Moscow could be behind the unrest in eastern Ukraine. In a daily briefing, State Department spokesperson Jen Psaki stated that during the phone conversation between US Secretary of State John Kerry and his Russian counterpart, the US chief diplomat “noted the Ukrainian Government’s assertion that this appeared to be a carefully orchestrated campaign with Russian support.”

“He called on Russia to publicly disavow the activities of separatists, saboteurs, and provocateurs, calling for de-escalation and dialogue, and called on all parties to refrain from agitation in Ukraine. He made clear that any further Russian efforts to destabilize Ukraine will incur further costs for Russia, and the ministers all discussed convening direct talks within the next 10 days between Ukraine, Russia, the United States, and the EU to try to de-escalate the tensions.”

The White House has also urged Russia to refrain from interfering in Ukraine. “We call on President Putin and his government to cease efforts to destabilize Ukraine,” White House spokesman Jay Carney said.

On Monday, a group of anti-coup activists seized government buildings in Ukraine's eastern cities of Donetsk and Kharkov, proclaiming the regions’ independence from Ukraine. Clashes between pro-independence demonstrators and security forces were also witnessed in Lugansk and Odessa.