A prolonged and increasingly vicious confrontation in eastern Ukraine turned into armed conflict yesterday as Ukrainian troops used helicopter gunships to seize back an airport that had been held by pro-Russian militiamen.
The attack at Kramatorsk came as ground forces with armour gathered around Sloviansk, which had become a symbolic stronghold for well-armed separatists.
At Kramatorsk, two of the aircraft made strafing runs, before two others landed troops. Four people were believed to have been injured, but claims of people killed, some of them civilians, could not be verified.
A stand-off developed afterwards, when protesters unfurled a banner saying "Shame on you! Go back home" and shouting while the soldiers fired in the air. About 10km away, the residents of Sloviansk marched towards their own small airstrip.
They were, they said, doing so to protect it from "fascists and Nazis being flown in" from the west of the country.
The outbreak of fighting raised deep trepidation that Ukraine, which has already lost Crimea to the Kremlin, could be entering into a civil war which might lead to the intervention of Russian President Vladimir Putin, who has repeatedly declared that he was prepared to act to protect ethnic Russians across the border.
The Russian Prime Minister, Dmitry Medvedev, warned Ukraine was on the brink of civil war, adding that he hoped the Kiev Administration "had enough brains to avoid a catastrophic escalation".
He blamed the Government in Kiev for creating a situation where people felt they had no choice but to rise up for their rights.
Key installations in 10 cities and towns have now slipped out of the control of Kiev and into the hands of protesters who are demanding a referendum on the future of the country. Repeated ultimatums for the gunmen to surrender have been ignored, severely damaging the credibility of the Government which came to power after the overthrow of Viktor Yanukovych.
The office of Ukraine's acting President, Olexander Turchinov, announced that the airfield had been captured in an anti-terrorist operation. There were also claims that a number of public buildings in the region had been retaken; but there was no immediate verification of that on the ground.
The operation at Kramatorsk appeared to be aimed at providing a landing site for positioning forces on one approach to Sloviansk.
Airborne forces, with Ministry of Interior police units, were at Kamianka, near Izyum, with armoured personnel carriers, light artillery and transport helicopters. Further back, an armoured bulldozer for clearing barricades had been parked near a hotel.
A senior officer who had just returned from a peacekeeping mission in the Democratic Republic of Congo, shook his head: "I come back to this. But one shouldn't be surprised, I think this was planned by some people a long time ago, maybe 15, 20 years ago."