A drop in violence and moves by both sides to withdraw heavy weapons from the front line had raised hopes a shaky two-week-old ceasefire could hold.
“In order to mislead OSCE representatives, the rebels are moving military equipment from the front line … and bringing it back at night,” military spokesman Andriy Lysenko said.
“There are signs the enemy is preparing for further offensives,” he said, naming as major targets government-held Mariupol, a strategic port city, and Artemivsk, north of the rebel stronghold of Donetsk.
While there was no shelling in the night, rebels shelled government troop positions 34 times on Saturday, wounding eight Ukrainian soldiers, Lysenko said.
On the other side, rebels said Ukrainian forces had fired mortar rounds and rockets in the Donetsk area 26 times in the past 24 hours, according to separatist DAN press service.
Senior rebel commander Eduard Basurin said on Sunday separatists continued the process of withdrawing heavy weapons from the front line under the eye of the Organization for Security and Cooperation in Europe, DAN reported.
The OSCE, which is monitoring the implementation of the peace deal, said on Saturday it had monitored the pull back of rebel equipment in parts of the Donetsk region and would check daily to see if the weapons remained in the areas they had been pulled back to.
It said it had also observed the withdrawal of two convoys in Luhansk region, but separatists had “prohibited the special monitoring mission from following either of these convoys to their end-points.”