A network of companies operated by a secretive Chinese tech firm has been trying to recruit recently laid-off U.S. government workers, according to job ads and a researcher who uncovered the campaign.

Max Lesser, a senior analyst on emerging threats with the Washington-based think tank Foundation for Defense of Democracies, said some companies placing recruitment ads were “part of a broader network of fake consulting and headhunting firms targeting former government employees and AI researchers.”

Little information is publicly available on the four consultancies and recruitment companies allegedly involved in the network, which in some cases shared overlapping websites, were hosted on the same server, or had other digital links, according to Reuters’ reporting and Lesser’s research.

The four companies’ websites are hosted at the same IP address alongside Smiao Intelligence, an internet services company whose website became unavailable during Reuters’ reporting. Reuters could not determine the nature of the relationship between Smiao Intelligence and the four companies.

The news agency’s attempts to track down the four companies and Smiao Intelligence ran into numerous dead ends including unanswered phone calls, phone numbers that no longer work, fake addresses, addresses that lead to empty fields, unanswered emails and deleted job listings from LinkedIn.

Lesser, who uncovered the network and shared his research with Reuters ahead of publication, said the campaign follows “well-established” techniques used by previous Chinese intelligence operations.

“What makes this activity significant,” he said, “is that the network seeks to exploit the financial vulnerabilities of former federal workers affected by recent mass layoffs.”

Reuters could not determine whether the companies are linked to the Chinese government or whether any former federal workers were recruited.

Asked about the research, three intelligence analysts told Reuters that the network appeared to be a prime example of how foreign-linked entities are trying to gather intelligence from staff members fired or forced into retirement by President Donald Trump and billionaire tech tycoon Elon Musk’s Department of Government Efficiency.

Once employed by the network, federal employees could then be asked to share increasingly sensitive information about government operations, or recommend additional people who might be targeted for willing or unwitting participation, the analysts said.

A spokesperson for the Chinese Embassy in Washington told Reuters in an email that China was unaware of any of the entities allegedly involved in the campaign and that Beijing respects data privacy and security.

A White House spokesperson said China was constantly trying to exploit the United States’ “free and open system” through espionage and coercion.

“Both active and former government employees must recognize the danger these governments pose and the importance of safeguarding government information,” the spokesperson said.

CNN reported on Feb. 28 that U.S. intelligence believes Russia and China are targeting disgruntled U.S. government employees, something both countries have done for years. The companies in the network — which posted job ads to Craigslist, LinkedIn and other job sites — could be concrete evidence that such operations are underway, Lesser said.

Reuters reported earlier this month that some U.S. government workers with top security clearances were not given standard exit briefings which, in part, cover what to do if approached by foreign adversaries.