Interim Ukraine President Oleksandr Turchyno said many rebels were killed in an offensive Friday in the eastern city of Sloviansk that cost Kiev two helicopters.
He said other rebels were arrested, though the offensive was not going as rapidly as hoped, the BBC reported.
The BBC said dozens were killed in Odessa, far to the west.
A day after saying it could not dislodge Russian-backed rebels from eastern areas of the country, the Ukrainian government launched a new operation.
Two helicopters were shot down, and both pilots killed, Western, Ukrainian and Russian media reported. The BBC show one SAM blowing up a helicopter.
Kiev claimed one of the helicopters was shot down by a ground to air missile, an item not normally available in army navy stores like ski masks and camouflage.
Russia called for an urgent meeting of the UN Security Council.
German Chancellor Angela Merkel [Unlink] met with US President Obama in Washington as a show of support.
Russian President Vladimir Putin issued an ultimatum Thursday to Kiev to remove its forces from eastern Ukraine. He also reneged on the Gevena agreement, accusing US, European Union and the Ukrainian government.
"While Russia is making efforts to de-escalate and resolve the conflict, the Kiev regime has chosen military aviation strikes on peaceful residential areas and started a punitive operation, literally destroying the last hope for the viability of the Geneva accords,” Putin spokesman Dmitry Peskov said.
“The Kiev regime ordered combat aircraft to fire at civilian towns and villages, launching a ‘punitive operation’ and effectively destroying all hope for the viability of the Geneva agreements.”
Russian media also claimed US mercenaries were in Ukraine, though if that were true then Kiev would be able to forcefully remove Russian rebels.
In fact, Russia has made no known moves to control the heavy armed rebels in the east and south of Ukraine.
Although Moscow promised to work to release seven members of the Organization of Security and Cooperation in Europe, they have now been held for a week by rebels. The team, including German nationals, was sent to eastern Ukraine to monitor events. Russian-back rebels also have detained Western journalists trying to determine whether Moscow forces were present in the area.
Russian soldiers had been found in the area by numerous reporters, some of the journalists were Russian speakers.
Putin, who denied for weeks that Russian soldiers were involved in the annexation of Crimea, later not only admitted they were present but boasted of it.
Now the Russian media, which since many staff were replaced in a purge earlier this year, is attacking every think the US, Europe or NATO does in the region.
They even said the US complaining about Russia’s involvement in the Ukraine would be like complaining about Moscow sending troops to Puerto Rico. The point was that Ukraine is in Russia’s sphere of influence. Apparently the writers did not know Puerto Rico is part of the US, and votes in American elections.