Speaking at a press conference on Monday, Lavrov said Kiev authorities don’t want or maybe cannot control the extremists who continue to control the situation in the country.

Lavrov's comments came after three pro-Russians were killed on Sunday in an exchange of fire with unknown attackers at a checkpoint near the town of Slovyansk.

He criticized Kiev’s government for violating the Geneva agreements from April 17.

Lavrov added Kiev authorities are still spinning out the implementation of constitutional reform in the country.

“Why were they waiting for so long to speak about the necessity of constitutional reform? Why are they spinning out the process?” he asked at the conference.

“They did nothing to eliminate the deep crisis in the country,” he added.

Russian foreign minister warned all attempts to isolate Russia will lead to a dead end.

Sunday's armed clash appears to be the first since an international agreement was reached last week in Geneva to ease tensions in eastern Ukraine.

It throws into question an already tentative truce that was supposed to be taking place over the Easter weekend.

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.

"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."

SHI/SHI