Constant cyberattacks on the U.S. Missile Defense Agency and its key weapons programs pose as great a threat as development of intercontinental ballistic missiles by Iran and North Korea, the admiral who heads the agency said Thursday.

Vice Adm. James Syring told a House Armed Services subcommittee that the agency has taken "inordinate" measures to defend its own networks, but he remains concerned about potential vulnerabilities among defense contractors.

The U.S. Missile Defense Agency develops and runs a multilayered system of defenses against ballistic missile attacks by potential enemies. The system includes ground-based interceptor missiles in Alaska and California as well as high-end radar equipment to detect attacks.