Poland has said the missile that hit a grain facility on Tuesday, killing two people near the border with Ukraine, was probably an "old" S-300 rocket, a Soviet-era missile system being used by both Russia and Ukraine.
NATO chief Jens Stoltenberg said it was likely being used as a Ukrainian air defence missile, but that Russia carried ultimate responsibility for the incident for having invaded Ukraine, triggering a now almost nine-month-old war. Russia at the time was firing scores of missiles at cities across Ukraine.
WHAT IS THE S-300?
* The S-300 is a family of surface-to-air missiles, originally developed by the Soviet Union. It was first put into operation in the late 1970s after a decade of development.
* There are several versions of the S-300 rocket, with different technical capabilities and ranges. The maximum range of the standard missile is 150 km (93 miles) and the warheads weigh 133-143 kg (293-315 lb), according to the Center for Strategic and International Studies (CSIS).
* It is unclear which version might have been used in Tuesday's incident.
* The S-300 is "more or less" a Russian equivalent to the U.S. Patriot surface-to-air missile system, said Siemon Wezeman, a senior researcher with the Arms Transfers Programme at the Stockholm International Peace Research Institute.
* S-300 missiles are intended to shoot down aircraft, drones and incoming cruise and ballistic missiles. Full S-300 launchers include detection radars that track incoming targets. Missiles are equipped with guidance systems to automatically latch on to targets. Several individual missiles can be fired simultaneously at multiple targets.
* The most recent version of the S-300 - called the Antey-2500, which was put into operation in the early 2010s - has a range of 350 km, according to a catalogue entry on Rosobornexport, Russia's state-run arms export agency. The system has "high tactical and technical characteristics that allow to use it for air defence of the most important administrative, industrial and military facilities, troop groups, coastal infrastructure and naval forces at stationing site," Rosoboronexport's website says.
* The S-300 is "a fairly potent system, but in Russia it was to be replaced in coming years by the more capable S-400, S-350 and S-500 systems," said Wezeman.
WHO USES THE S-300 MISSILE?
* It is used by both Russia and Ukraine, as well as 18 other countries including NATO members Greece, Slovakia and Bulgaria, according to CSIS, a Washington-based think tank.
* Russia has appeared to use repurposed S-300 missiles to strike ground targets during the war in Ukraine - a sign of potentially dwindling missile supplies, military analysts say.
* Moscow has previously sold S-300 missiles to Venezuela, China, Iran and Egypt, among other countries.
* Russia has deployed S-300 missiles in Syria and stationed them on the peninsula of Crimea, which Moscow annexed from Ukraine in 2014.
* According to Russian military media outlets, the S-300 missile system was first used in conflict during the 2020 war between Azerbaijan and Armenia over Nagorno-Karabakh.
(Reporting by Jake Cordell and Michael Kahn. Editing by Mark Heinrich)
