SLOVYANSK, Ukraine (AP) -- Ukraine launched what appeared to be its first major assault against pro-Russian forces who have seized government buildings in the country's east, with fighting breaking out in the early hours on today around a city that has become the focus of the insurgency. Three deaths were reported in early fighting.
Russian President Vladimir Putin's spokesman said the offensive "effectively destroyed the last hope for the implementation of the Geneva agreements" which were intended to defuse the crisis.
Two Ukrainian helicopters were shot down and two of their crewmembers killed this morning, both sides said. The Ukrainian Security Service said one of the helicopters was shot down with a surface-to-air missile, which it said undercut Russia's claims that the city is under control of civilians who took up arms.
Stella Khorosheva, a spokeswoman for the pro-Russian militants, said one of their men was killed and another injured. She offered no further details.
Putin's spokesman, Dmitry Peskov, said the Kremlin had sent an envoy to Ukraine's southeast to negotiate the release of foreign military observers who were captured by pro-Russian militia in Slovyansk.
The action came a day after Putin said that Ukraine should withdraw its military from the eastern and southern regions of the country. Russia has massed tens of thousands of troops along the Ukrainian border as it warns Ukraine's military not to move against the insurgents in the east.
The Ukrainian Security Service said one helicopter was shot down with a surface-to-air missile, a sophisticated weapon, which they said countered Russia's claims that the city is under control.