Despite a recent agreement between the Chinese and United States not to commit acts of cyber espionage, on Sept. 28, the FBI issued warnings to at-risk firms that Chinese hackers “have compromised and stolen sensitive military information,” according to The Daily Beast.

The FBI is highly confident Chinese computer spies have stolen sensitive information, including credentials and passwords, from firms that provide engineering and technical services to the Navy and the Marine Corps. Evidence suggests that the data was stolen from the Navy’s SeaPort contracting program, which employs 2,400 companies.

This warning comes just three days after President Barack Obama and President Xi Jinping signed an historic agreement to rein in economic espionage on Sept. 25.