Known by the NATO code 'Hip' and built by Russians, Mi-17 helicopters are being supplied by the US to aid the Ukrainian troops on the battlefield.
Originally purchased from Russia for Afghanistan's deposed government, the US is now supplying the Russian-built helicopter ironically in response to Moscow's invasion of Ukraine.
Primarily used for utility missions like troops and cargo transport, the Mi-17 can be armed with forward-firing rockets and other weapons and has been seen across social media being used by Ukrainian forces defending against Russia's invasion.
The US supplying Ukraine
In April, US President Jo Biden announced his approval of an $800m (£610m) security package to Ukraine.
That package would dramatically expand the scope of military aid the US was supplying to Kyiv.
Among the artillery systems, artillery rounds and armoured personnel carriers in the package, Biden "approved the transfer of additional helicopters" – the Mi-17s would come at a crucial time for Ukraine's outgunned and outmanned military.
President Biden agreed to send artillery and helicopters to Ukraine after Ukrainian President Zelensky called for support.
He approved the $800m (£610m) in military assistance for Ukraine, which included artillery and helicopters, to bolster its defences against a Russian offensive in the country's east.
The arms package included 18 of the US Army's 155mm howitzers and 40,000 artillery rounds, two air surveillance radars, 300 Switchblade "kamikaze" armed drones, and 500 Javelin missiles designed to knock out tanks and other armour.
Ten counter-artillery radars were also included. They are used to track incoming artillery and other projectiles to determine their point of origin for counter-attacks.
Eleven Soviet-era Mi-17 helicopters were also crucially part of the US package – the United States had previously planned to provide to Afghanistan before Mr Biden last year decided to fully withdraw from the country.
The Mi-17s are personnel transports, yet can effectively function in an attack role as they can be armed with cannons and rockets, and provide close air support.
The Pentagon previously had sent five Mi-17s to Ukraine, according to Pentagon press secretary John Kirby.
The Mi-17 is an improved version of the Mi-8 specifically designed for improved capabilities at high altitudes and in hot weather conditions.
The helicopter is equipped with excellent navigation and information system and a modern design that enables safe day and night transport of personnel even under very adverse weather conditions.
WATCH: $800m of weapons the US is sending Ukraine explained.
Significance of the donation to Ukraine
President Biden announced the aid after a call with Ukrainian President Volodymyr Zelensky to coordinate the delivery of the assistance, which he said included artillery systems, artillery rounds and armoured personnel carriers, as well as the helicopters.
"This new package of assistance will contain many of the highly effective weapons systems we have already provided and new capabilities tailored to the wider assault we expect Russia to launch in eastern Ukraine," Mr Biden said in April.
The president added that the US would continue to work with allies to share additional weapons and resources as the conflict continues.
Mr Biden said: "The steady supply of weapons the United States and its allies and partners have provided to Ukraine has been critical in sustaining its fight against the Russian invasion.
"It has helped ensure that (Russia President Vladimir) Putin failed in his initial war aims to conquer and control Ukraine. We cannot rest now."
Russian military equipment being used against Moscow's forces in Ukraine is not unfamiliar.
The military personnel in Ukraine, a former Soviet state, have far more experience using Russian helicopters such as the Mi-17 than US Chinooks or Black Hawks, so would require far less if any training once received the Mi-17s.
Cover image: US Department of Defense.