KIEV — Ukraine accused pro-Russian rebels on Monday of carrying out the heaviest artillery attacks on government positions in six months and warned of signs the conflict was escalating despite a cease-fire deal.
The military said 400 rebel fighters supported by tanks had attacked government forces around the village of Starohnativka, 50 kilometers (30 miles) north of the Kiev-held port city of Mariupol. The rebels denied attacking government troops.
Control of Mariupol could help the rebels form a corridor to the Crimea Peninsula, which Russia annexed from Ukraine last year.
A cease-fire deal signed in mid-February has failed to stem the violence in the eastern conflict zone. Both sides regularly accuse the other of violating the terms of the peace agreement and casualties are reported almost daily.
"This brazen attack by the occupiers took place against a background of an escalating situation in east Ukraine," military spokesman Andriy Lysenko said, describing rebel shelling in the past 24 hours as the heaviest since a battle for the town of Debaltseve in February.
Ukrainian troops halted the offensive using artillery and regained lost ground, Lysenko said.
Senior separatist commander Eduard Basurin denied the rebels had attacked government troops and accused Ukraine of intensive shelling, rebel press service DAN reported.
Earlier another military spokesman, Yaroslav Chepurny, said the incident showed that Mariupol city remained under threat from separatists.
"The main danger [to Mariupol] — is in the further approach routes to the city — from the direction of Granitnoye, Starohnativka. We knew about this and were prepared," he said.
One Ukrainian servicemen was killed, one was missing in action and 16 were wounded in the past 24 hours, Lysenko said.
More than 6,500 soldiers, separatists and civilians have been killed since fighting between Ukrainian troops and rebels seeking independence from Kiev erupted in April 2014, according to UN estimates.