"The Russian officers appointed to command posts in formations and units of illegal armed forces during a recent rotation are trying to improve the combat capabilities of the subordinate units. In particular, they make the local leaders constantly increase the number and duration of drills, including the intensive use of combat vehicles," Ukrainian Defense Ministry press secretary for Anti-Terrorist Operation issues Oleksandr Motuzianyk said at a briefing in Kyiv on December 31 with reference to a report by the ministry's Defense Intelligence Department.

Read alsoDonbas war update: First day of 2018 doesn't bring peace"And this does not allow militants to properly service military equipment. For instance, two engines of two tanks broke during the exercises in a unit of the so-called 1st Army Corps within one week. Several more vehicles require an overhaul due to intensive use," Motuzianyk said.

However, he claims, the intensive use of military vehicles indicates possible preparations for an offensive.

"The enemy's enhanced attention to the use of military vehicles indicates a possible preparation for offensive actions. At the same time, the neglect by the Russian officers of the maintenance of the equipment indicates a probability of its replenishment from the territory of the Russian Federation," he added.