Ukrainian President Volodymyr Zelensky spoke by phone with his US counterpart Donald Trump on Friday. They spoke after it emerged that the US had suspended some key arms deliveries to Kiev. Washington justified the move by citing concerns about a shortage of relevant weapons for US needs and an ongoing stockpile review. However, according to the former administration and an analysis reported by NBC News, the deliveries to Ukraine will not threaten US stockpiles.

The suspension of deliveries concerns missiles for the Patriot air defense system, Stinger anti-aircraft missiles, guided artillery shells, ammunition used by F-16 fighters and Nasams air defense systems, as well as Hellfire missiles, rounds for GMLRS long-range precision-strike rocket launchers and AT4 anti-tank systems, according to the Financial Times, unnamed American and Ukrainian representatives said.

Washington justified its move by concerns about dwindling supplies and said it was preceded by a review of the number of weapons and ammunition in US military warehouses."(Former President Joe) Biden emptied our country by giving them (Ukraine) weapons, and we have to make sure there are enough for ourselves," Trump said.

But Biden-era national security adviser Jake Sullivan questioned this reasoning. According to him, the suspension of supplies primarily concerns the Ukraine Security Assistance Initiative (USAI) program, through which weapons are purchased for Kiev directly from manufacturers and which allows the replacement of material sent to Ukraine with newer equipment.

The USAI supplies “come from government procurement, not from Pentagon stockpiles, and are separate from orders for the U.S. military,” Sullivan said. “The administration may not want to say it, but the reality seems to be that the president is cutting U.S. security assistance to Ukraine.”

NBC News also wrote, citing three US officials, that according to an analysis conducted by senior military officers, aid to Ukraine would not jeopardize the supply of ammunition to the US military.

Ukrainians, Europeans and Trump's allies are surprised

The Ukrainian Defense Ministry previously said that it had not received any official notification regarding the suspension or revision of the schedule of deliveries of US military aid and requested a telephone conversation with its American counterparts.

European officials were also surprised by the Pentagon's decision, Bloomberg reported. In part, they are trying to find ways to compensate for the already reduced US aid to Kiev. European allies are demanding an explanation from the White House. Other sources suggest the decision could be softened or canceled altogether.

According to Politico, the Pentagon's move caught even some usually well-informed members of Congress and State Department officials by surprise, including President Trump's allies.

Kyiv wants to buy American weapons

Zelensky said on Friday that he and Trump had discussed air defense and cooperation in strengthening the protection of Ukrainian skies. According to the FT, Zelensky also wanted to discuss potential purchases of American weapons during the phone call with Trump. Ukrainians have repeatedly indicated that they are willing to buy American weapons directly from Washington. In April, Zelensky said they were ready to spend $50 billion for this purpose.

Politico reported this week that Zelensky wants to ask Washington for permission to purchase American weapons through Europe. Several European governments are reportedly exploring plans to purchase American-made weapons from their defense budgets for delivery to Ukraine, according to the website.

The money spent would count towards NATO's defense spending, but there are no concrete commitments yet. Transfers of European-purchased American weapons to Ukraine would have to be approved by Washington, which is under discussion, according to Politico.

Moscow attacks with record number of drones

As The Wall Street Journal (WSJ) noted, for example, the restriction on American weapons supplies could not have come at a worse time, as Russia is already using ballistic missiles capable of evading the radar of the Patriot air defense system to attack Ukrainian cities, and is sending out a new record number of drones every few days.

Most recently, on Friday night, Moscow attacked with almost 540 drones, the most so far, and another eleven ballistic missiles.

The WSJ reported on Wednesday that Russia has launched 20,100 drones so far this year, compared to 2,315 for the same period in 2024. This is according to data analyzed by the WSJ and the Center for Information Resilience (CIR), a British organization that analyzes open-source data.

While the number of cruise missiles and ballistic missiles fired has decreased in this comparison, Russia's latest tactic is to launch multiple drones and missiles in a single attack to overwhelm Ukrainian air defenses.

Moreover, many of the drones sent are dummies that do not carry charges, but confuse and unnecessarily exhaust Ukrainian air defenses.

Russians are improving drones, making them harder to shoot down

The Russians are also continuously improving the Shahed suicide drones they use to attack Ukrainian cities, Radio Free Europe/Radio Liberty (RFE/RL) reported, citing Kiev-based expert Oleksandr Vysikan, who studies Russian drones.

According to him, they have a new, more powerful warhead and use a variety of advanced technologies, including protected 16-channel satellite antennas, which makes it difficult for Ukrainian electronic warfare systems to effectively engage them. “More channels means more electronic jamming is needed (to block the signal),” Vysikan explained.

The drones also now have a secondary navigation system that uses GSM mobile network technology, allowing operators to track the drones in real time, even when the primary navigation system is disrupted.

"This system allows the drone's trajectory and behavior to be monitored remotely. If it deviates or crashes, operators know it has been neutralized," Vysikan added.

ISW: Russian battlefield gains will accelerate

The shortage of American weapons will likely accelerate Russian gains on the battlefield, the Institute for the Study of War (ISW) noted, among others, adding that the same was true during previous interruptions or delays in supplies from Washington. Most recently this spring, when the Russians intensified operations in the Kursk region during the interruption of arms supplies and intelligence sharing.

The freeze on US supplies will likely force Ukraine to conserve ammunition and scale back operations, although the exact timeline for the halted supplies remains unclear, notes ISW.

However, the deputy commander of one of the Ukrainian battalions told The Washington Post that the soldiers were now focusing on holding defensive lines and conserving resources, rather than advancing.

Ukrainians have already reported in recent days that the Russians have approached Pokrovske and Kostyantynivka in the Donetsk region and are trying at all costs to break through the borders of the Dnipropetrovsk region.