Federal authorities in New York made two arrests Monday in connection with the establishment of a Chinese-government-run police station in Manhattan, where officials allegedly monitored pro-democracy activists.

The clandestine station, run by China’s Ministry of Public Security (MPS), was announced alongside a complaint charging 34 individuals accused of working at a “troll farm” the MPS runs to target Chinese dissidents online.

Although it appears the office was helping Chinese citizens with services like driver’s licenses in some cases, consular activities require approval from U.S. authorities, and law enforcement said Monday the station’s employees were not registered as foreign agents.

“New York City is home to New York’s finest, the NYPD. We don’t need or want a secret police station in our great city,” said Breon Peace, U.S. attorney for the Eastern District of New York, in a press conference. “Just imagine the NYPD opening an undeclared, secret police station in Beijing. It would be unthinkable.”

Lu Jianwang and Chen Jinping are charged with conspiring to act as foreign agents, which could carry up to five years in prison, as well as obstruction of justice, which carries up to 20 years of jail time. 

Authorities are not fully aware of all the activities at the station, which is in Chinatown, because Jianwang and Jinping deleted information from their phones following initial outreach by U.S. authorities, according to authorities. 

Peace called the deletion of possible evidence an impediment in the case but noted authorities had some evidence that MPS directed the station to spy on a California-based pro-democracy activist.

“The secret police station appears to have had a more sinister use,” he said. “The Chinese National Police appear to have been using the station to track a U.S. resident on U.S. soil.

China has been accused of establishing some 100 such stations across the globe, with Ireland, Netherlands, and Spain taking actions to address them.

The case represents a significant advancement by law enforcement, with the U.S. now the first country to make arrests in connection with China’s overseas police stations.

The Chinese Embassy did not immediately respond to a request for comment.

A separate filing brings charges against 34 Chinese nationals believed to live in China, in connection with an online effort to “intimidate [People’s Republic of China (PRC)] dissidents residing abroad and sought to suppress the dissidents’ free speech.”

The case charges each with conspiracy to transmit interstate threats and conspiracy to commit interstate harassment for their role in the MSP’s “912 Special Project Working Group.”

“This task force operates as an internet troll farm, creating thousands of fake online personas which they use in a coordinated plot to harass, disparage, and threaten dissidents and activists throughout the world. People the PRC perceives as threats to the legitimacy of the Chinese Communist Party,” Peace said.