The National Counterintelligence and Security Center warned on Tuesday that China’s intelligence services were using deceptive efforts to recruit current and former U.S. government employees.

The center, along with the F.B.I. and the Pentagon’s counterintelligence service, said in an advisory that foreign intelligence agencies were posing as consulting firms, corporate think tanks and other organizations to recruit former U.S. officials.

The American government has long said that China uses social networks to secretly recruit people. But former U.S. officials say China now sees an opportunity as the Trump administration shuts down agencies, fires probationary employees and pushes out people who had worked on diversity issues.