The weapons include SA-8, SA-10, SA-12 and SA-14 mobile air defense systems, CNN reports, referring to an unnamed senior US official.
All the weapon types date back to the Soviet-era and are also widely used by the Ukrainian military.
The report refers to the systems by their NATO designations. The SA-8 is the 9K33 Osa mobile short-range surface-to-air missile system developed in the 1960s, and the SA-14 is the 9K34 Strela-3 man-portable air defense missile system (MANPADS) from the same decade.
The SA-10 is the S-300 long-range anti-aircraft missile system, while the SA-12 is its upgraded variant (S-300V) developed in the 1980s.
The Armed Forces of Ukraine have been documented as having used all four types during the first weeks of the Russian invasion, as well as capturing a small number of SA-8s from Russia and receiving PPZR Pioruns, the modernized Polish-made versions of the SA-14s, from Poland.
According to the report, the systems have been acquired from NATO member states and are “on their way” to Ukraine.
Currently, multiple NATO members, including Poland, Bulgaria, Croatia and Slovakia, use one or more type of the listed systems, while the US has also been documented acquiring such weapons or capturing them in previous conflicts.