Ukraine's military said its forces killed as many as 200 rebels in fighting in Donetsk as dozens of tanks and other military vehicles crossed the border into Ukraine from Russia.
''Insurgents who were shelling Ukrainian troop positions at Donetsk Airport yesterday were killed by government troop artillery strikes,'' Ukraine's defense ministry said on Facebook today.
''Four separatist tanks, two armored personnel carriers, two howitzers, and an infantry combat vehicle were destroyed, and up to 200 insurgents were killed.''
The death toll, which couldn't be independently confirmed, is the biggest reported number of troops or fighters killed during repeated breaches of a 5 September truce. Earlier, the Ukrainian government said it had suffered more than 100 killed and about 600 wounded since the cease-fire came into force.
As tensions between the former Soviet republics threatened to escalate into open war, Ukraine's army is preparing ''for an adequate reaction,'' military spokesman Andriy Lysenko told reporters in Kiev today. He said pro-Russian rebel shelling of government troops with surface-to-surface grad missiles, mortars and artillery had killed five soldiers and wounded 16 in the last 24 hours.
The military standoff is coming to a head after Ukraine and its allies accused separatists of undermining peace efforts and violating the truce agreed in Minsk, Belarus by holding elections in Donetsk and Luhansk on 2 November that the US and the European Union have called illegitimate.
Russian President Vladimir Putin has said that Ukraine's ''civil war'' isn't subsiding as cities continue to come under shelling and the civilian death toll rises. Putin denies that Russian forces are involved in the conflict.
''Russia continues to supply manpower and military vehicles to Ukraine's Donbas,'' Lysenko said, referring to eastern Ukraine. ''Yesterday, 32 tanks, 16 howitzers, and 30 trucks with ammunition and manpower crossed the border from Russia'' into Luhansk.
Andrei Bobrun, a Russian Defense Ministry spokesman, wouldn't immediately comment when reached by phone in Moscow.
Russia's RIA Novosti state news service quoted Andrei Purgin, deputy premier of the self-proclaimed Donetsk People's Republic, as saying that Ukraine had begun a large-scale offensive against the separatists in the east. Purgin said he sees ''all-out war'' and said Ukrainian forces had broken the truce.