KIEV (Reuters) - One Ukrainian soldier was killed and two wounded in separatist eastern territories in the past 24 hours, military spokesman Andriy Lysenko said on Wednesday, as NATO's top commander voiced concern over renewed fighting.
Ukraine's military and pro-Russian rebels have accused each other of intensifying attacks and building up weapons on the frontline over the past few days, putting further strain on a two-month-old ceasefire deal.
Separatist officials said one rebel fighter had been killed and five wounded as a result of attacks from the Ukrainian side in the past 24 hours, the separatist news agency DAN reported.
Six Ukrainian soldiers were reported killed on Tuesday -- one of the heaviest losses for government troops in weeks.
Lysenko described the situation as unstable. Rebels "actively used guns, grenade launchers (and) yesterday the enemy twice opened tank fire on our forces near Pisky," he said, referring to a village near rebel-held Donetsk.
He accused Russia of massing troops and military equipment on the other side of the border in Belgorod region, bordering Ukraine. "Ten kilometers from the Ukrainian-Russian border Russian military forces consisting of 50 armored vehicles and 2,000 servicemen have been sighted," he said.
Separatist officials accused Ukrainian government troops of firing heavy artillery at Shyrokyne, a village east of the government-held port city Mariupol, which has seen some of the fiercest fighting since the February truce came into effect.
Earlier on Wednesday, NATO's Supreme Allied Commander, U.S. General Philip Breedlove, urged Russia to stop fuelling the conflict.
"Concerned by renewed fighting in Ukraine. Vital all sides pull back verifiably, Russia stops fuelling conflict," he said on Twitter.
Russia has repeatedly denied accusations from Kiev and the West that it is supporting pro-Russian rebels with troops and weapons in eastern Ukraine, where more than 6,000 people have been killed since last April.
Reporting by Pavel Polityuk; Writing by Alessandra Prentice; Editing by Crispian Balmer