A gun battle at a checkpoint manned by pro-Russian separatists in eastern Ukraine has left five dead, it has been claimed.
Russia's state-run Rossiya 24 news station said the five died when gunmen attacked the post near the city of Slavyansk, which is under separatist control.
A separatist interviewed by Reuters at the scene said three of the dead were with the pro-Russian militia.
The attack had happened at 2am local time, he said.
"We had three dead, four wounded," a fighter called Vladimir told the news agency at the checkpoint, where there were two burned-out jeeps.
But Sky's Katie Stallard, who has been to the scene, said there are inconsistencies in the separatists' accounts and there is no coherent evidence to back up what they are saying.
Reuters TV footage of the scene showed two bodies, one of which appeared to have gunshot wounds to the head and face.
Kiev's interior ministry said one person had been killed and three injured in an armed clash.
It said police were trying to establish more details about what happened.A map showing the location of Slavyansk
The separatists claimed the attackers were members of Right Sector, a hard-right fringe group that was part of the anti-Russia movement whose protests in Kiev and western Ukraine forced the former president to leave office.
Right Sector denied being involved, instead blaming Russian special forces in an illustration of the claim and counter claim that has been rife during the crisis.
The event prompted the self-declared leader of the pro-Russian faction in Slavyansk to appeal to Moscow to send in peacekeeping troops.
Ukraine and many in the West fear reports of clashes could provide a pretext for Russia to seize more Ukrainian territory.
Russia's foreign ministry said it was outraged by the shootout, describing it as a "provocation".
Pro-Russia separatist gunmen maintain a firm grip over a string of towns across eastern Ukraine, despite an international deal signed last week demanding they leave state buildings they are occupying.
On Sunday afternoon they declared a curfew in Slavyansk.
Russia, the US, the European Union and Ukraine struck a deal on Thursday aiming at de-escalating the crisis, part of which involves the separatists agreeing to lay down their arms.
Authorities in Kiev, who vowed to remove the separatists, said they have suspended military operations against the rebels until after Easter to give the militia time to comply with the agreement.
The deadline runs out on Monday, after which the US and the EU have said they will consider further sanctions against Russia.
Earlier, Ukraine's Prime Minister Arseny Yatseniuk accused Russian President Vladimir Putin of having "a dream to restore the Soviet Union".
Meanwhile, the heads of the Ukrainian and Russian Orthodox churches traded barbs over the crisis in the country as believers flocked to church for Easter services.