Kiev has said no evidence has been found that the ultra-nationalistic Right Sector could have been involved in the death of protesters, who were killed in a shootout near the city of Slovyansk, eastern Ukraine, on Sunday.
"We have to officially declare once again that any evidence capable of proving the Right Sector's involvement in the bloody shooting incident in Slovyansk is absent," the Ukrainian Foreign Ministry said in a statement.
Three supporters of the "Donetsk people's republic" were killed and another thee were injured in a raid on a checkpoint manned by protesters just outside of Slovyansk early on April 20.
It is not known whether any of the attackers were killed or injured.
The Ukrainian Foreign Ministry confirmed that an investigation had been launched immediately after the shooting near Slovyansk.
The Russian Foreign Ministry, for its part, expressed outrage at the incident.
"The Russian side condemns the militants' provocation, which indicates that the Kiev authorities do not want to subdue and disarm the nationalists and extremists," the Russian Foreign Ministry said.
"The fact that this tragedy occurred after an agreement was signed in Geneva on April 17 following four-party talks between representatives of Russia, the United States, the European Union and Ukraine arouses surprise. The agreement carries a call to refrain from violence, intimidation and provocations. The Russian side insists on the rigorous implementation of the commitment to de-escalate the situation in southeastern Ukraine, assumed by the Ukrainian side," Moscow said.
"The Easter truce has been violated. Innocent peaceful citizens died as a result of the armed attack staged by militants of the so-called Right Sector. City residents managed to seize the attackers' cars, in which weapons, aerial images of the district and Right Sector symbols were found," it said.
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