A network of CIA-backed spy bases, including 12 near the border with Russia, have been built over the past eight years in Ukraine.
Bases which - reports the New York Times - are part of the close collaboration between the American agency and Kiev.
A crucial partnership in the battle against Russia, which dates back more than a decade, and which also includes the CIA's training of an elite Ukrainian commando unit - Unit 2245 - to capture Russian drones and communications equipment to enable the intelligence agency American to study and codify Moscow's encrypted systems.
The war in Ukraine enters its third year and the collaboration between the CIA and Kiev is one of the cornerstones that allow Ukraine to defend itself.
The partnership - which also includes bases entirely funded by the CIA on Ukrainian soil - did not begin with the war but has its roots back at least 10 years ago and has been able to transform Ukraine into one of Washington's most important partners against Russia.
In the last eight years - reports the New York Times - CIA has built 12 secret locations in the Ukrainian forest on the border with Russia.
In 2016, the CIA began training an elite Ukrainian commando unit - Unit 2245 - to capture Russian drones and communications equipment to enable the US intelligence agency to study and code Moscow's encryption systems.
The CIA has also helped train a new generation of Ukrainian spies operating in Russia, Europe, Cuba and other areas where there is a strong Russian presence.
These intelligence networks are more important than ever right now with Ukraine struggling on the battlefield.
But on the horizon is the risk of a lack of funds to continue operating at current levels should Republicans in Congress halt or end aid to Kiev.
To reassure Ukrainian leaders, CIA director Williams Burns secretly flew to Kiev in recent days, in what was his tenth visit since the start of the invasion.
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