For more than a decade, the United States has maintained a secret intelligence collaboration with Ukraine, which is now essential to both nations' efforts to confront Russia, The New York Times reported.

Adam Entous and Michael Schwirtz held interviews with numerous sources from Ukraine, Europe, and the US, which led them to discover that the CIA funds and equips hidden bases where Ukrainian troops keep tabs on Russian spy satellites and listen in on discussions between Russian commanders.

The intelligence collaboration between Washington and Kiev is critical to Ukraine's capacity to fight, the authors note. The CIA and other US American intelligence organizations gather intelligence for targeted missile attacks, monitor Russian army movements, and assist espionage networks.

However, this cooperation was not formed during the war, and not only Ukraine benefited from it.

Read more: The CIA; a covert army of mayhem across the world

The listening station in a dense Ukrainian forest is part of a CIA-supported network of spy sites built over the last eight years, which includes 12 covert outposts near the Russian border.

Around 2016, the CIA started training an elite Ukrainian commando squad known as Unit 2245, which captured Russian drones and communications equipment so that CIA experts could reverse-engineer them and break Moscow's encryption protocols. (One officer in the regiment was Kyrylo Budanov, who is now the general.)

The CIA also assisted in the training of a new generation of Ukrainian spies who worked in Russia, Europe, Cuba, and other Russian-controlled areas.

The relationship is so strong that CIA officials stayed in a distant location in western Ukraine when the Biden administration evacuated US soldiers in the weeks leading up to the war in February 2022. During the war, the officers conveyed important intelligence, such as where Russia planned to strike and which weapons systems they would deploy.

Ivan Bakanov, who was then head of Ukraine’s domestic intelligence agency, the SBU, expressed that “without them, there would have been no way for us to resist the Russians, or to beat them."

Secret CIA training program helped Ukraine prepare for Russia special op.

In March 2022, Yahoo News reported that a secret CIA-run training program in Ukraine helped Kiev prepare for Russia's special military operation in the country

The US Central Intelligence Agency's program kicked off in 2014 when the conflict in Donbass started, but the Biden administration pulled out all its CIA personnel from Ukraine before Russia started its military operation in the country, the report added, citing former officials.

Washington ran its covert CIA training program from Ukraine's eastern frontlines, and it was made possible through previously existing assets for the agency, which made them illegible to stay without new legal determination, according to Yahoo News.

The report also revealed that the CIA sent a very small number of its paramilitary officers, which did not exceed a dozen, to eastern Ukraine as part of its training program.

The CIA's personnel taught the Ukrainians certain sniper techniques, how to use Javelin anti-tank missiles, means of evading digital tracking used by Moscow to locate troops, and how to use covert communication tools, to name a few, the report revealed.