The U.S. Marine Corps has deployed a cutting-edge unmanned surface-to-ship missile system at a base in Okinawa Prefecture since July, informed sources said Wednesday.

The Navy-Marine Expeditionary Ship Interdiction System, or NMESIS, has already been used in drills at the base on the main island of the prefecture, people familiar with the matter said, adding that the first-ever NMESIS deployment in Japan is believed to be aimed at checking China's maritime expansion.

Mounted on an unmanned vehicle, the remote-control missile system can swiftly be positioned along the coastline to attack enemy ships more than 180 kilometers away.

The system is scheduled to feature in Resolute Dragon drills to be held jointly by the Marines and the Ground Self-Defense Force in Okinawa Prefecture and other parts of the country later this month to practice retaking an occupied remote island, the sources said.