The mass culling of workers from federal payrolls will have a “devastating” impact on cybersecurity and national security, a top former National Security Agency official said on Wednesday.

Rob Joyce, former NSA director of cybersecurity, told the House Select Committee on the Chinese Communist Party of the harm from aggressive threats to cut U.S. government employees.

“Eliminating probationary employees will destroy a pipeline of top talent, essential for hunting and eradicating PRC threats,” Joyce said at the hearing on the threat posed by the People’s Republic of China’s cyber operations targeting U.S. critical infrastructure, telecommunications and other sectors.