The new Ukrainian government struck the separatists in this eastern province with a major military offensive on Monday, battling them over an important provincial airport in ground fighting that lasted for hours. The rebels were left scattered and shaken, just one day after a successful national election they had tried to disrupt.
The airport battle was the first time the Ukrainian military had moved so aggressively against the separatists, who took over government buildings in two eastern provinces in March, after weeks of low-grade military maneuvers meant to stop their spread to other areas.
There was no immediate indication that the Ukrainian military's operations extended any further than the strategically important airport and surrounding area. Experts said that while the military's attack might have put the separatists on the defensive, it was unlikely to stop their power.
As fighting lasted into a rainy evening, the military claimed to have evicted the separatists from the airport, and had cordoned off the area with roadblocks. But the sporadic sounds of weapons fire could still be heard, and it was not clear that government soldiers were in full control. The airport remained closed, and some local news outlets reported that it was burning.
"I don't see this ending anytime soon," said Oxana Shevel, a political science professor who specializes in Ukraine at Tufts University in Boston. "The Ukrainian government is saying, This is where we draw the line." Its ability to retake the airport, she said, "doesn't dramatically change things."