The American-made Patriot surface-to-air missile system has been a workhorse for Kyiv in defending against Russian attacks.

The US Army plans to spend more than $1.3 billion on Patriot missiles for the fiscal year beginning Oct. 1, and has quietly quadrupled its overall purchase target for the air defense weapon that has proven critical not just for Ukraine but also for US forces in the Middle East.

Since the Patriot's introduction in 1981, around 1,100 have been acquired by the U.S. Army. Approximately 200 of the produced launchers have been exported.