The U.S. Navy has for the first time dispatched two of its medium-sized unmanned prototype vessels to Yokosuka Naval Base as it prepares to increase both the number and use of multidomain drones in the Indo-Pacific region amid growing tensions with China.

Formally known as unmanned surface vessels, the autonomous Mariner and Ranger arrived at Yokosuka, home to the U.S. Seventh Fleet, on Monday as part of a long-range deployment that began last month at their home port just north of Los Angeles.

The Pacific crossing, the first-ever by U.S. Navy unmanned ships, was made with a small crew on board as the vessels are still test platforms.