Two Chinese nationals have been charged with spying inside the United States on behalf of Beijing, including by taking photographs of a naval base, coordinating a cash dead-drop and participating in efforts to recruit members of the military who they thought might be open to working for Chinese intelligence.

The case, filed in federal court in San Francisco and unsealed Monday, is the latest Justice Department prosecution to target what officials say are persistent efforts by the Chinese government to secretly collect intelligence about American military capabilities, a practice laid bare in startling fashion two years ago with China's launching of a surveillance balloon that US officials ultimately shot down over the coast of South Carolina.

"This case underscores the Chinese government's sustained and aggressive effort to infiltrate our military and undermine our national security from within," Attorney General Pam Bondi said in a statement announcing the case. "The Justice Department will not stand by while hostile nations embed spies in our country; we will expose foreign operatives, hold their agents to account, and protect the American people from covert threats to our national security."