Moscow is outraged by the latest armed incident in Ukraine Saturday night, and demands that Kiev de-escalate tensions in its southeast region, the Russian Foreign Ministry said Sunday.

"On the night of Saturday, the Easter armistice was broken in Slavyansk. The attack of the armed militants from the so-called Right Sector claimed lives of innocent civilians," the ministry said in a comment published on its website.

State-run Rossiya 24 news station reported early Sunday that a group of unidentified gunmen attacked a checkpoint controlled by pro-Russia protesters, resulting in the death of three protesters and two gunmen.

According to the Ukrainian Interior Ministry, there was an armed clash between two groups of individuals at a roadblock in Slavyansk in Donetsk region. One person was killed and three others got shot wounds.

"The Russian side is enraged by the militant provocation which is an indication of the reluctance of the authorities in Kiev to bridle and disarm nationalists and extremists," the ministry noted.

Calling the incident a tragedy, the ministry said it was surprising that the clash took place after the signing of the Geneva agreement.

Russia insisted on Ukraine's "strict fulfillment" of its commitment and de-escalation of tensions in the southeastern region, said the ministry.

The United States, Russia, Ukraine, and the European Union concluded talks in Geneva Thursday after signing a statement, asking all sides to refrain from violence, intimidation or provocative actions as part of initial steps to restore order in the country.

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