A Russian military expert has said the United States has started to restrict its military assistance to Ukraine and linked what he believed to be a cooling of Washington's support for Kyiv to the actions of Ukrainian President Volodymyr Zelensky.

The comments by Arsenal of the Fatherland editor Alexei Leonkov come a day after the Biden administration announced another $1 billion in new military aid for Ukraine comprised of rockets, ammunition and arms from the U.S. Department of Defense stocks.

On Tuesday, Leonkov wrote on his Telegram channel about the U.S.-supplied M142 High Mobility Artillery Rocket Systems (HIMARS), which are a game-changing weapon for Kyiv that have allowed its forces to hit Russian command centers and ammunition depots.

But he said that "the United States is beginning to limit the list of future arms supplies to Ukraine." Regarding HIMARS, the U.S. had "planned 20, and delivered 16."

Russian military expert Alexei Leonkov has said that the U.S. is restricting military assistance to Ukraine, including the F-16s. Above, Ukrainian President Volodymyr Zelensky delivers a speech in Kyiv on August 7, 2022, and Portuguese Air Force F-16 fighters fly over the Tagus River on April 3, 2022, in Lisbon. Getty Images

"Now they are refusing to supply F-16s, temporarily," Leonkov said, referring to the fighter jets that Ukraine has been calling for, adding that Poland had delivered 232 tanks and Slovakia, 11 MiG-29 jets.

"Although what is temporary can become permanent," he said, adding that "'scandals and revelations' had grown around the persona of Zelensky in the Western media."

While he did not specify what he meant by "revelations," Leonkov then said that contrary to Zelensky's announcement of a counter-attack in Kherson, little had changed on the ground.

Russian state media have also made much of the dispute between Zelensky and Amnesty International, which accused his forces of endangering civilians by deliberately setting up bases in residential areas.

"Ukraine's preparation for a counter-offensive around Kherson had been carried out, with forces allocated and deadlines set," wrote Leonkov, although "with nil result."

"Therefore, attacks on Zelensky by the Western media and restrictions on the supply of weapons are not accidental, these are links in the same chain," he said.

"Zelensky has received a 'black mark' and his fate is determined."

There is no evidence that the U.S. has refused to supply F-16s although the jets have been part of Ukraine's repeated calls for western military assistance against Russian aggression to include aircraft.

Last month, Air Force Chief of Staff General Charles Q. Brown Jr. told Reuters that the U.S. and its NATO allies were considering training Ukrainian pilots, and that "different platforms" could go to Ukraine such as Swedish Gripen jets or the French Dassault Rafale.

Congress approved the Defense Authorization Act last month, which included helping move Ukraine's reliance on Soviet-era MiG-29s and Sukhoi planes and would allow for Ukrainian pilots to be trained to fly F-15s and F-16s.

Meanwhile, Monday's announcement by Colin Kahl, the U.S. undersecretary of defense for policy, raised the assistance by the Biden administration to Kyiv to more than $9 billion since Russian troops invaded Ukraine on February 24.

In a statement, a senior U.S. defense official told Newsweek that the security assistance the U.S. was providing to Ukraine "is enabling critical success on the battlefield against the Russian invading force."

"We are working around the clock to fulfill Ukraine's priority security assistance requests, delivering weapons from U.S. stocks when they are available, and facilitating the delivery of weapons by Allies and partners when their systems better suit Ukraine's needs."

Newsweek has reached out to the Ukrainian defense ministry for comment.

Update 08/09/22, 1:01 PM ET: This article has been updated with a Pentagon response.