The key to how Ukraine’s military may have acquired these Soviet-era rarities and their ammunition could literally be "hidden in plain sight."
The press service of the 3rd Separate Assault Brigade released a video showing its fighters firing a Soviet 240mm M-240 mortar. They noted that the Ukrainian Armed Forces have several such artillery systems, one of which was assigned to the fire support company of the 3rd Separate Assault Brigade.
Read more: Destruction of Ammunition at Engels Airbase Officially Confirmed – russians Did Indeed Store Cruise Missiles in the Open
The very appearance of such a video can be considered significant news. Until now, mentions of the M-240 in Ukrainian service had surfaced only twice on social media, in 2022 and 2023. However, even then, no details were available about which units operated these Soviet 240mm mortars.
Particularly noteworthy is the confirmation that the Ukrainian Armed Forces have multiple M-240s. For a long time, it was believed that only a single mortar existed in Ukrainian service—supposedly taken from the World War II Museum in Kyiv. However, it was later confirmed that the original exhibit remains in place.
After this, the most plausible explanation emerged: some M-240 mortars were likely stored at military depots or in the reserves of military academies in Ukraine, from where they were later transferred to frontline units.
However, another possibility is worth considering. According to some sources, Romania may have received 12 large-caliber 240mm M-240 mortars from the Soviet Union in 1971. If Romania did acquire these artillery systems and their ammunition, this could have contributed to Ukraine’s ability to field 240mm mortars and obtain the necessary munitions to use against russian occupiers.
The phrase "may have received" is used because, for example, The Military Balance did not record the presence of M-240 mortars in Romania as of 1990 (or later). However, to be fair, The Military Balance in 1990 also did not list Soviet MiG-29 fighters in Romania, even though deliveries of these aircraft began in the late 1980s.
M-240 Characteristics
The M-240 has a rate of fire of one round per minute and is loaded from the breech. Deploying the system from transport to combat position takes 20–25 minutes. The mortar can be towed at speeds of up to 40 km/h, and its crew consists of 11 personnel.

The M-240 fires high-explosive shells 53-F-864 and 53-F-865, each weighing 130.7 kg, as well as the 3F2 rocket-assisted projectile, which weighs 228 kg. The mortar was produced between 1951 and 1958, with a total of 329 units manufactured.
Read more: Ukrainian Long-range Weapons Hit Warehouse with Kh-555, Kh-101 Cruise Missiles for Tu-95,Tu-160 Bombers at russian Engels Airbase