For half a century, America’s top geopolitical rival used a spy base in nearby Cuba to steal U.S. military secrets by listening in on phone and data communications.

Twenty years after the Soviet Union shut down that post, China may be picking up where Moscow left off.

Beijing’s reported efforts at surveillance from Cuba are reminiscent of Lourdes, a Soviet-built listening post just south of Havana that once employed thousands of personnel to eavesdrop on sensitive U.S. phone and data communications. But where the Soviet Union sought ideological conquests in Cuba and throughout Latin America, China’s efforts are rooted in burgeoning economic relations.