As Ukraine's acting President Oleksandr Turchynov told parliament on Tuesday that the military was engaged in an “anti-terrorist operation” in the east of the country, Russia's Prime Minister Dmitri Medvedev warned against the use of force and said that Ukraine is again "on the brink of civil war."
Pro-Russian activists in cities across the east have risen up against Kiev's authority, with many calling for the opportunity to vote on their continued inclusion in Ukraine.
"Overnight, an antiterrorist operation began in the north of Donetsk. But it will be phased, responsible and balanced," Turchynov announced, according to the Interfax news agency. "The purpose of the actions, I stress once again, is to protect the citizens of Ukraine."
According to CNN, "A spokesman for Ukraine's National Security and Defense Council, Evgen Rojenyuk, confirmed that a National Guard battalion made up of 350 troops was sent to eastern Ukraine from Kiev on Tuesday morning."
Updates to follow....
UPDATE (11:25 AM EST): Ukrainian commander says those who do not lay down their arms 'will be destroyed'
The Guardian reports:
The commander of the anti-terrorist operation, General Vasily Krotov, confirmed to journalists that government forces had seized an airfield in Kramatorsk. As he spoke, four helicopters arrived and flew off loaded with special forces troops.
A large armoured column and special forces moved towards Slavyansk – seven buses filled with 100 paratroopers, 20 tanks and armoured personnel carriers moved within 40 kilometres (25 miles) of the city and set up a checkpoint to control traffic leading to the economically depressed industrial city of 100,000 that has been under effective control of separatist gunmen since Saturday.
"They must be warned that if they do not lay down their arms, they will be destroyed," Krutov said, claiming that the wave of unrest in Ukraine's east was being led by Russian forces. He said more than 300 Russian forces had infiltrated neighbouring Luhansk region on Monday.
"We need to destroy this foreign invader," Krotov said. "We have among these spies Russian military, professionals with long experience in all sorts of conflicts."
UPDATE (11:18 AM EST): 4 Protesters Killed in Army Attack on Airfield in Eastern Ukraine
RIA-Novosti, the Russian state-run news agency, reports:
At least four protesters were killed and two other wounded on Tuesday as the Ukrainian troops stormed an airfield in Ukraine's eastern city of Kramatorsk, a spokesman for local People's Militia told RIA Novosti.
"There are four dead and two wounded at the airfield. They are all militia," the source said, adding that no casualties among the government troops had been reported.
"The fighting for the airfield is over as the militia has reterated and the Ukrainian side took control of the airfield," he said.
Previous ultimatums from Kiev for the pro-Russian activists to relinquish their positions had gone unfulfilled. But as the New York Times reports, "The first indication that the operation represented more than just words this time was a modest Ukrainian military checkpoint established on a highway north of the town of Slovyansk, which has been controlled by militants since Saturday."
Witnesses confirmed to the Times that a dozen armored personnel carriers were parked on the highway and flying Ukrainian flags about 25 miles, north of the town, but that "no credible reports of confrontations" had yet occurred.
In a phone call Monday night, President Obama spoke with Russian President Vladimir Putin and again warned that further sanctions would be imposed by the west if Moscow did not end its interference in eastern Ukraine. Putin, however, rebuffed Obama's claims of Russian interference and said that it was incumbent on the U.S. and its European allies to use their influence with the government in Kiev to make sure violence does not break out.
In a statement made from Beijing, Russian Foreign Minister Sergei Lavrov called Ukraine's decision to use military action against the uprisings in the east as “unacceptable.” He reiterated Putin's claim as well, saying that Moscow's involvement among the Pro-Russian activists in eastern cities was “the biggest load of nonsense I have ever heard.”
Media outlets report that Russia has threatened to cancel international talks scheduled for later this week if Ukraine follows through with its threat to oust those occupying government buildings.
In a related development, the White House confirmed on Monday that CIA chief John Brennan did visit Kiev over the weekend, though spokesman Jay Carney would not detail who he met or why, exactly, he was there. As the AP reports: "Ousted Ukrainian President Viktor Yanukovych is accusing the CIA of being behind the new government's decision to turn to force. But the CIA denies that Brennan encouraged Ukrainian authorities to conduct tactical operations."