STORY: This hulking German-supplied howitzer rumbles out of its forest hideout.It only has a few minutes to fire before slipping back under cover, to evade Russian surveillance in the skies above.Ukrainian artillery units are playing a cat-and-mouse game to avoid Russian drones hunting high-value weapons like this self-propelled Panzerhaubitze 2000.Crews, including the 43rd Artillery Brigade Reuters recently visited, say they face increasing harassment from enemy drones, now a staple of Russia's arsenal.This battery commander, who goes by his call sign "Lyova" says his unit had been directly hit four times by Russian high-tech attack drones."They use a lot more strike drones, like "Privet-82". They have different variations of "Lancet" drones which were upgraded. They have cumulative, high-explosive warheads. There were attacks before, but not the same amount. Now it's really scary."Western-supplied artillery, like the German howitzer, is a priority target for Moscow. It has pledged to focus its strikes on these types of weapons.Senior battery officer Andriy Stavnychyi."The situation has become more difficult because they have a lot of electronically warfare equipment. They don't allow our "birds" to fly over their territory, thus it's harder to detect targets and hit them. The other reason are their kamikaze strike drones. They have an abundance of ZALA and Orlan drones. Sometimes it happens that there's lots of work for the day, but we can't move because something is always flying above. If these "birds" could be shot down or jammed, we'd then be more effective and could work more."Like other Ukrainian artillery units, the 43rd Brigade faces a critical shell shortage that limits the howitzer's potential - forcing it to fire far fewer shells per day.Ukrainian troops across the sprawling front are anxiously awaiting shipments from a long-delayed $61-billion U.S. military aid package.Repairing the vehicle is also a challenge.The availability of spare parts is limited and the navigation system frequently malfunctions and is difficult to fix on the battlefield.Stavnychyi, like many others, is calling for more electronic warfare systems to jam the Russian drones."The main problem here is spare parts and shells. But even if there were parts and shells, you'd have the problem of enemy 'birds.' So everything needs to work together in a system: electronic warfare and surveillance, artillery. Then our hit percentage would be much higher. Here is what I think."