Russia should be responsible for a fatal shootout between unidentified gunmen and pro-Moscow activists in the eastern Ukrainian town of Slavyansk, authorities said Sunday.
"Armed lawbreakers and saboteurs who are terrorising the local population around Slavyansk ... have turned to cynical provocation," Xinhua quoted the Ukrainian Security Service as saying in a statement.
Describing the incident as a "staged attack," the statement said no group was present "other than the saboteurs and crime figures, supported and armed by officers of Russia's GRU (military intelligence)".
Meanwhile, the Right Sector, a Ukrainian nationalist group blamed by Moscow and pro-Russia activists for the shooting, denied involvement and also accused Russia's special forces of staging the attack.
The group, which was at the vanguard of street protests that forced the ouster of President Viktor Yanukovych in February, said the charge against it was "lies" and "propaganda" designed to portray eastern Ukraine as ungovernable by Kiev.