Alejandro Ernesto/Reuters
The base was set up in 1964 after the Cuban missile crisis and is 155 miles from the U.S. coast. Havana shut it down in 2001 because of financial issues and American pressure.
"Lourdes gave the Soviet Union eyes in the whole of the western hemisphere," a former head of Russia's foreign intelligence service, Vyacheslav Trubnikov, told Kommersant. "For Russia, which is fighting for its lawful rights and place in the international community, it would be no less valuable than for the USSR."
Once the Soviet Union's largest outside of its territory, the facility was manned by about 3,000 military and intelligence personnel who intercepted signals coming from and to the U.S. territory and provided communication for the Russian vessels in the West.
Kommersant reported that the agreement was finalized during Russian President Vladimir Putin's visit to Havana last week. Moscow also recently agreed to write off 90% of Cuba's debt dating back to the Soviet era, which totaled around $32 billion.
Putin has been emboldened ever since NSA contractor Edward Snowden flew to Moscow from Hong Kong on June 23 of last year after stealing an estimated 1.7 million documents from NSA servers in Hawaii.
"All I can say is - finally!" one Russian source told Kommersant.