Ukrainian towns and cities have suffered months of intensifying Russian bombardment. But on the battlefield, Russia's offensive is showing signs of losing steam. More than four years into its invasion, the Russian defence ministry's statements claiming to have captured towns and villages in Ukraine have become less regular. And in some areas, Ukraine's forces have managed to gain a foothold. Read moreHas Russia given up on Kinburn Spit, its westernmost foothold in Ukraine? In April and May, the Russian army lost more ground in Ukraine than it gained, according to an AFP analysis of data from the US-based Institute for the Study of War (ISW). Although these territorial gains are too small to change the situation on the ground, they illustrate the growing difficulties that the Russian army faces. "The Russian army's advance is proceeding at an extremely slow pace," Russian military expert Alexander Khramchikhin told AFP. Even though the Russian army is bigger and better equipped than its Ukrainian counterpart, the use of drones has created a "dead zone" on either side of the front line. Unless the Ukrainian army's resources are "completely depleted", then an acceleration in Russian advances is difficult to foresee, said Khramchikhin. Ukrainian forces have meanwhile "largely halted" Russia's spring-summer offensive, the ISW said in a report earlier this month. 'All of Ukraine' Unable to launch major offensive operations on the front, Russia has taken to launching infiltration operations: sending small groups of soldiers behind enemy lines to hold key positions until reinforcements arrive. The tactic has had some success, particularly during the capture of the Ukrainian logistics hub of Pokrovsk late last year, although it can take a long time to bear fruit. Instead of sweeping advances across the front line, Russia has concentrated its military efforts on capturing the Ukrainian stronghold of Kostyantynivka, a former industrial town in the Donetsk region. Read moreHow Russia’s 'thousand cuts' tactic is straining Ukraine’s frontline forces Russia also seems to have scaled back its war aims. After declaring last June that "all of Ukraine" was Russia's, and threatening to take the regional Ukrainian capital of Sumy, President Vladimir Putin has since said his army aims solely to seize the Donbas – the eastern regions of Donetsk and Lugansk.