MOSCOW, February 2. /TASS/. Ukraine's use of experimental "FrankenSAM" defense systems has highlighted gaps in NATO's own arsenals, The Business Insider said quoting a military expert.

The weapons, named for a combination of Frankenstein's monster and the acronym for surface-to-air missiles, are produced by the US and Ukraine and made by cobbling together different systems to create new weapons that can take down missiles, drones, and aircraft.

They often combine US weaponry with Soviet-era equipment. Some have involved converting American-made AIM-9M Sidewinder missiles typically shot from planes so that they can be fired from a ground-launching system.

But the fact that this strategy is being pursued shows just how much NATO countries, including the US, are missing ground-based air defense systems, according to Mark Cancian, a retired US Marine Corps colonel and a senior advisor at the Center for Strategic and International Studies.

"The FrankenSAMs fill a critical gap" for Ukraine as its allies don't have enough ground-based air defenses to give it, Cancian said.

He said Ukraine desperately needs ground-based air defenses, with Russia launching major drone and missile strikes on cities and towns across the country.

The way Russia is fighting now also shows how NATO needs these kinds of weapons if it wants to be ready for future conflicts. "But it simply doesn't have enough, after member states stopped investing in the weaponry after the Cold War," Cancian told the Business Insider.