China now has four electronic listening posts in Cuba, including one just 70 miles from the US base in Guantanamo, new satellite analysis shows.

The findings mean that Beijing may be tuning in to highly sensitive communications by the US military across the entire lower 48 states, especially in southern states such as Florida and Texas, brimming with army, navy and air force bases.

Titled Secret Signals, Decoding China’s Intelligence Activities in Cuba, the fresh analysis of existing satellite imagery comes from the Center for Strategic and International Studies (CSIS), a Washington DC-based thinktank.

It looks at four sites, Bejucal, Wajay and Calabazar, all near Havana, and, on the other side of the Caribbean island, El Salao, near Guantanamo.

The military base at Bejucal, in the hills above the capital, is notorious for hosting Soviet nuclear weapons during the 1962 Cuban missile crisis, the flashpoint that most historians regard as the closest the world has ever come to nuclear war.

The CSIS researchers note that Cuba, whose state-run economy is on the brink of collapse, has both ideological and practical reasons for helping Beijing snoop on the US. China, meanwhile, in addition to the strategic advantages offered by the island’s proximity to the US, wants to prop up one of the few remaining fellow communist regimes.

“Florida alone is home to the major space-launch complex at Cape Canaveral, the headquarters of both the US Southern Command and Central Command, and multiple submarine and other bases,” the report warned.

But China is not the only adversary of the west with a military footprint in the Caribbean. On Wednesday, it was confirmed that the Admiral Gorshkov, the Russian frigate that recently docked along with a nuclear-powered submarine in Cuba, is now in Venezuela.

Caracas has not publicly announced the warship’s arrival but it was spotted from a distance by journalists at a military facility in the port city of La Guaira.

In Havana, civilians were even allowed to tour the frigate. But the Maduro regime’s secrecy around the Gorshkov’s visit intensifies the mystery over the strategic purpose of the Russian vessel’s presence in the autocratic South American nation.