In 2003, it became apparent that the system was not ready for deployment. In August, two high-ranking military officials expressed concern that the S-400 was being tested with "obsolete" interceptors from the S-300P system and concluded that it was not ready for deployment. The completion of the project was announced in February 2004, and in April, a ballistic missile was successfully intercepted in a test of the upgraded 48N6DM missile. In 2007, the system was approved for service. Russia has accepted for service the 40N6 long-range missile for the S-400 air-defence system, a source in the domestic defense industry told TASS news agency in October 2018.