Russia tried to destroy an advanced U.S.-built Patriot air defense system with a hypersonic missile, two undisclosed U.S. officials told CNN on May 12.
The attack failed, as Ukraine's air defense intercepted the missile using the Patriot system.
The Air Force reported that a Patriot was used to destroy a ballistic missile over Kyiv Oblast that Russia launched from MiG-31K in its territory at around 2:30 a.m. on May 4.
The interception marked the first known successful Ukrainian use of the advanced air defense system only weeks after its arrival.
The military leadership first decided not to publish information about the downing of the missile due to "quite obvious" reasons.
"The fact that this intercept was conducted by a Ukrainian crew that was trained in Oklahoma, but had no U.S. advisers on the battlefield, is even more of a feather in the cap for the Pentagon," an undisclosed source told CNN on May 8, calling it a major return on investment.
Russian dictator Vladimir Putin has boasted about the capabilities of Russia’s hypersonic weapons and cast them as capable of overcoming all existing air defense systems.
The intercept also has likely caused a severe amount of uncertainty for Russia, raising the question of whether Ukraine has a sustainable countermeasure against hypersonic ballistic missiles, according to CNN's sources.