A Pro-Russian militant walks past burnt cars near a checkpoint that was the scene of a gunfight overnight near the city of Slaviansk, yesterday. Photo: Reuters

At least three people were killed in a gunfight in the early hours yesterday near a Ukrainian city controlled by pro-Russian separatists, shaking an already fragile international accord that was designed to avert a wider conflict.

The incident triggered a war of words between Moscow and Ukraine’s western-backed government with each questioning the other’s compliance with the agreement, brokered last week in Geneva, to end a crisis that has made Russia’s ties with the West more fraught than at any time since the Cold War.

The separatists said armed men from Ukraine’s Right Sector nationalist group had attacked them. The Right Sector denied any role, saying Russian special forces were behind the clash.

Failure of the Geneva agreement could bring more bloodshed in eastern Ukraine, but may also prompt the United States to impose tougher sanctions on the Kremlin – with far-reaching consequences for many economies and importers of Russian energy.

The incident triggered a war of words between Moscow and Ukraine

The deal signed in Geneva last week by the European Union, Russia, Ukraine and the United States agreed that illegal armed groups would go home in a process to be overseen by Europe’s OSCE security watchdog.

So far, the pro-Russian militants have shown little sign of budging from public buildings in the east, though there was some hope of progress after Kiev said it would not move against the separatists over Easter, and international mediators headed to eastern Ukraine to try to persuade them to disarm.

Local media reports that one occupied town hall near the city of Donetsk had been vacated and was again flying a Ukrainian flag prompted the US ambassador to Kiev to speak of progress. But OSCE monitors cautioned that it would take time.

And the shootings near Slaviansk – already a flashpoint for tensions between Ukraine’s rival camps – are likely to make that task even harder, hardening the view of the many Russian-speakers in eastern Ukraine that they cannot trust Kiev.

“The Easter truce has been violated,” the Russian foreign ministry said in a statement. “This provocation ... testifies to the lack of will on the part of the Kiev authorities to rein in and disarm nationalists and extremists.” The town’s self-appointed pro-Russia mayor placed a curfew on the town and appealed directly to Russia’s Vladimir Putin to consider sending in peacekeeping troops – an outcome Ukraine tried to avoid by holding back its poorly resourced forces.

Ukraine’s SBU security service accused Moscow agents of a faking a “cynical provocation” at Slaviansk.