Russia has accused Ukraine of breaking the accord thrashed out in Geneva last week after a raid on a checkpoint in Slovyansk left three pro-Russian separatists dead.
Moscow blames right-wing Ukranian nationalists for the killings.
Kyiv is set to launch an investigation into the attack.
Speaking in Moscow Foreign Minister Sergei Lavrov said: “The most important thing now is to prevent any kind of violence. This is the first point of the Geneva agreement, the first demand to all those confronting each other in Ukraine.
‘But in this and other respects, the Geneva agreement is not being implemented, and moreover, steps are being taken – above all by those who seized power in Kyiv – to crudely violate the Geneva agreement.”
The shooting comes as pro-Russian militias continue to occupy government buildings in eastern Ukraine defying the deal to leave.
As tensions continue to rise Russian President Vladimir Putin has agreed changes to the law to make it easier for former citizens of the Soviet Union to acquire Russian citizenship.
The new rules follow Russia’s annexation of Ukraine’s Crimea peninsula.