 Ukrainian officers complain of receiving Western weapons systems when they're no longer relevant. Unnamed Ukrainian military officials said there is an unfortunate pattern of the West finally sending weapons when they are no longer relevant for the current battlefield dynamics, Politico reported, citing sources, while Ukraine's Western allies have provided tens of billions of military aid and equipment, some of the more advanced systems pledged such as the F-16 fighter jet have been slow walked and have yet to reach the battlefield. At the same time, Russia has been steadily adapting its defensive capabilities to counter new Western weapons as they arrive. The official explained that Russia has been testing its air defense posture and has likely deployed its radar and anti-air missiles in a manner that would render much of the F-16's offensive capabilities ineffective. After a series of damaging strikes on Russian positions using the long-range storm shadow and scalp missiles, Russia changed its tactics and positions, an official said. Weapons systems become redundant very quickly because they're very quickly countered by the Russians. He said adding, the Russians are always studying. They don't give us a second chance, and they're successful in this. The official said that Ukraine also needs more traditional weapons and munitions, such as the more than a million artillery shells currently being sourced by the Czech-led initiative. Elsewhere, the officials said domestic Ukrainian politics have contributed to the unfavorable battlefield situation. All of these issues are present against the backdrop of a nearly six-month delay in military assistance from the US. Zelensky said in late March that Ukraine could soon be forced to retreat without an infusion of aid, which the officials agreed with. Ukraine's ability to hold off the ongoing offensive has been mostly thanks to Russian mistakes on the battlefield, but the official said that Russia will likely be able to penetrate the front line and to crash it in some parts. Ukraine's security service and main directorate of intelligence under the Defense Ministry were behind the attack on Russian Nizhnykansk oil refinery in Tatarstan on Tuesday morning, Ukrainian media reported, with reference to unnamed sources within the intelligence department. A Ukrainian long-range drone hit the primary oil processing facility at the Nizhnykansk refinery, after which fire broke out there, according to the report. The capacity of this processing unit is 8 million tons of oil, which amounts to 2.6% of the total annual refining of the Russian Federation per year. In addition, this plant is among the five largest refineries in Russia. We continue to work systematically to ensure that Russia has fewer and fewer opportunities to finance the war of aggression against Ukraine. We will continue to cut off oxygen to the gas station country in order to minimize the flow of petrodollars to the military budget of the Russian Federation, the source told media. According to Baza, at least three people were injured at the refinery. This is the Taniko oil refinery in the city of Nizhnykansk in the Republic of Tatarstan. The region's governor confirmed the attack on the refinery, but in his statement, he did not specify the name of the refinery that was attacked. Russian media has confirmed that Nizhnykansk oil refinery was hit, while stressing that the technological process was not disrupted. The Russian media also claimed that drones allegedly attacked a hostel in a special economic zone of Alabuga, and that two people were injured during the attack. Ukraine in recent months has stepped up attacks on Russia's oil refiners in a bid to impact Kremlin's highly lucrative trade in refined products. Kiev believes its drone attacks on Russia, the world's second largest oil producer, are justified because Ukraine has suffered large-scale damage to its infrastructure from Russian airstrikes since the start of Russia's full-fledged invasion of the country in February 2022.