NEW YORK, August 30. /TASS/. It will be too risky to use US-made F-16 fighter jets on the frontline in Ukraine because of high efficiency of Russian air defense systems, a US military expert said.

"The idea of F-16s flying over the front lines and breaking the stalemate is just not viable - it’s just too dangerous," said Mark Cancian, a senior adviser with the International Security Program at the Washington-based Center for Strategic and International Studies (CSIS). "Russian air defenses are very formidable."

In addition, "there are tens of thousands of parts on an F-16" that need to be delivered to ensure proper maintenance of the aircraft, "and that pipeline has to go into Ukraine."

In his words, F-16s require 16 hours of maintenance per one flight hour. Besides, the cost of one flight hour is nearly $27,000.

On August 20, Ukrainian President Vladimir Zelensky said he has reached a "breakthrough agreement" with the Netherlands on the delivery of 42 F-16 fighter jets. Denmark also agreed to transfer 19 F-16 fighter jets to Ukraine, six of which will arrive before the New Year. The Danish Air Force has about 30 fighter jets that will be decommissioned when the country switches to the more modern F-35 jets. The Dutch Air Force has 42 of such planes.

Commander of US Air Forces in Europe and Africa General James Hecker said earlier at a meeting with a Washington-based group of military observers, in which TASS participates, that it could take up to five years to prepare Ukrainian F-16 squadrons for participation in combat operations. At the same time, according to him, the transfer of aircraft by the West will not radically change the course of hostilities in Kiev's favor.

Russian Foreign Minister Sergey Lavrov warned that Russia would perceive the transfer of fighter jets to Ukraine, one of whose modifications can carry nuclear weapons, as "a threat from the West in the nuclear sphere.".