Your first sentence doesn't make any sense. If it's one party, eg Russia or China, then these aren't two unknown parties working together, they're one party operating at two locations. Russia and China both have the reach to operate in Cuba and China, both are devoted adversaries of the US when it comes to politics, espionage and military.

Further, it may be espionage gear that both Russia and China are now using, such that one party (Russia) is using it in Cuba, and the other party (China) is using it in China.

That is all a lot more plausible than the US severely harming their own people at their living quarters in multiple locations around the globe.