The FBI has arrested two alleged Chinese Communist Party agents for running “secret police stations” in the heart of New York to spy on and intimidate exiles.

The arrests of Lu Jianwang, 61, and Chen Jinping, 59, are the first criminal charges worldwide over Beijing’s attempts to bypass diplomatic and legal norms to harass and persecute its citizens beyond its borders. Dozens of alleged Chinese “overseas police stations” have been discovered abroad, including in the UK, the Netherlands and Canada, prompting authorities to launch police investigations.

The US justice department on Monday revealed what it said is evidence of expanding espionage and security activity by the Chinese government on American soil.

The Manhattan indictment was one of three separate cases to be revealed, suggesting more brazen activity by China inside the US.

The charges allege the two defendants were operating the illegal overseas police outpost in Chinatown in lower Manhattan on behalf of the ministry of public security of the People’s Republic of China (PRC). Prosecutors say an official with the Chinese National Police directed one of the defendants, a US citizen, to help locate an activist of Chinese descent living in California.

“In other words, the Chinese national police appear to have been using the station to track a US resident on US soil,” Breon Peace, the US attorney for the eastern district of New York, said.

When news of the search was first reported, the Chinese embassy in Washington downplayed the role of the outposts, saying they were staffed by volunteers who helped Chinese nationals perform routine tasks like renewing their driver’s licences back home.

New York prosecutors say a tip-off of the search led to the men deleting phone communication made with their Chinese handlers. The pair were charged with obstruction of justice and accused of destroying evidence as well as conspiring to act as agents of the People’s Republic of China.