Completing the deployment of one of two new U.S.-developed land-based missile defense batteries to protect against North Korean attacks is expected to take about six years, officials said Monday.

The schedule, as suggested by the U.S. side, for installing an Aegis Ashore missile battery would take one year longer than Japan is planning, and the Defense Ministry is expected to call on Washington to cooperate on a speedier deployment.

Defense Minister Itsunori Onodera told reporters that the two batteries, including Lockheed Martin Corp.'s cutting-edge SSR radar, will together cost ¥268 billion ($2.4 billion).