Ukraine’s Donetsk suffers escalation of violence

DONETSK, Ukraine—Some of the heaviest fighting in months erupted in and around the rebel stronghold of Donetsk early Sunday, hours after an unmarked column of weaponry and armed vehicles arrived in the eastern Ukrainian city.

Artillery fire, machine-gun rounds and mortar blasts shook Donetsk and its suburbs for hours late Saturday and early Sunday. Barrages of artillery fire were shot from the densely populated, rebel-held city center toward the disputed Donetsk airport and Ukrainian-held suburbs in the north. Ukrainian government forces also appeared to be firing on rebel-held territory in and around Donetsk.

Ukrainian forces and Russia-backed rebels have been exchanging artillery volleys nearly every day since agreeing on a cease-fire in September that began fraying hours after it was signed. Now worries are mounting over a possible return to full-blown warfare, a week after Russia-backed rebels held elections that Ukraine and the West denounced as illegal.

The conflict could also simmer for months with daily artillery fire punctuated by periodic outbursts but no major territorial gains. The Ukrainian government, having failed in its quest to receive Western military aid, is hesitant to reopen an offensive in a war that it can’t win if Russia continues to back the rebels. The rebels have little incentive to stop fighting, given their war-focused leadership and the lack of a bargain with Kyiv on territory or political independence.

For the Kremlin, pressuring the rebels to give up the fight would be seen as a concession, something Moscow seems unlikely to do at present, given the U.S. and Europe have made clear there isn’t likely to be relief from sanctions soon.

The cease-fire signed in September in Minsk by Ukraine, Russia, the rebels and the Organization for Security and Cooperation in Europe brought a wave of prisoner exchanges, a freeze in territorial gains and a broadly reduced level of violence.

But fighting never fully stopped, as the two sides continued to battle in particular over the airport and the Ukrainian-held town of Debaltsevo farther east. The tattered peace is threatening to fray even further, as the fighting around the airport intensifies.

In a statement over the weekend, OSCE Chairman Didier Burkhalter expressed concern “about a resurgence of violence in the eastern regions of Ukraine and about activities leading to more fragility instead of further stabilization of the situation.”

European Union foreign policy chief Federica Mogherini said Sunday that OSCE reports of “convoys in separatist held areas with substantial amounts of heavy weapons, tanks and troops without insignia moving westwards represent a very worrying development.”

Ukrainian forces and the Russia-backed rebels regularly trade accusations over which side is responsible for restarting the fighting. Both sides say they are returning fire only in defense.

An expanded version of this report appears at WSJ.com