Ukraine said on Tuesday that it downed six Russian hypersonic Kinzhal missiles in a single night, in what would be a major setback for Moscow's efforts to develop an unstoppable next-generation weapon.
It was not clear which air defence system Kyiv used to shoot down the missiles, but last week the US military confirmed that Ukraine had shot down a Kinzhal missile using the US-produced Patriot system.
Here is what you need to know about the Patriot:
WHAT IS THE PATRIOT MISSILE SYSTEM?
The Patriot, which stands for Phased Array Tracking Radar for Intercept on Target, is a theater-wide surface-to-air missile defense system built by Raytheon Technologies Corp and considered one of the most advanced air defense systems in the US arsenal.
The system was first used in combat during the 1991 Gulf War, with batteries protecting Saudi Arabia, Kuwait and Israel, and later used during the US invasion of Iraq in 2003.
CAN PATRIOTS KNOCK OUT HYPERSONIC MISSILES?
The Patriot system was designed before hypersonic weapons were sent to battlefield and Raytheon has not said publicly that the is effective against a missile flying at hypersonic speeds (anything above five times the speed of sound). While the US said that the Patriot system brought down last week's Khinzal missile, it was not clear if that missile was traveling at hypersonic speed at the time.
While Russia's Kinzhal missile may reach speeds of up to 7,600 mph (12,350 kph), "Russia’s designation of the Kinzhal as a 'hypersonic' missile is somewhat misleading, as nearly all ballistic missiles reach hypersonic speeds (i.e. above Mach 5) at some point during their flight," the Center for Strategic and International Studies said in a March 2022 report.
HOW DOES THE PATRIOT SYSTEM WORK?
The Patriot is a mobile system that usually includes powerful radar, a control station, a power generator, launch stations and other support vehicles.
The system has different capabilities depending on the type of interceptor - the missile fired from the battery - used.
The earlier PAC-2 interceptor uses a blast-fragmentation warhead, while the PAC-3 family of missiles uses more advanced hit-to-kill technology.
It is not clear what kind of Patriot systems have been donated to Ukraine but it is likely that Kyiv has at least some of the newer PAC-3 CRI interceptors.
The system's radar has a range of over 150 km (93 miles), the North Atlantic Treaty Organization (NATO) said in 2015.
WHAT DOES IT COST?
A newly produced single Patriot battery costs over $1 billion, with $400 million for the system and $690 million for the missiles in a battery, according to CSIS.
HOW DOES THE PATRIOT HELP UKRAINE?
Ukraine has said it needs more air defense systems to protect against the barrage of missile and drones strikes from Russian forces.
The United States has also provided a pair of National Advanced Surface-to-Air Missile Systems (NASAMS) to Ukraine.
While the Patriot system is designed to intercept threats like aircraft and ballistic missiles, it can also shoot down the "kamikaze" drones Russia has frequently sent to hit Ukrainian critical infrastructure. But it would be an extremely expensive way to destroy drones that only cost thousands of dollars.
HOW WIDELY IS THE SYSTEM USED?
Raytheon has built more 240 Patriot systems and they are currently used by 18 countries, including the United States. The system has been in high demand in the Middle East because of the threat posed by Iran to the region.
According to Raytheon, the system has intercepted more than 150 ballistic missiles in combat since 2015.