MISAWA AIR BASE, Japan (AP) — The U.S. Air Force has deployed two of its most advanced long-distance surveillance drones to a base in northern Japan over the past week, enhancing its ability to monitor nuclear activities in North Korea and Chinese naval operations.

The deployment of the two unarmed Global Hawk drones to Japan, a key U.S. ally, is intended to demonstrate Washington’s commitment to security in Asia as part of its rebalancing of forces to the Pacific. But it will likely rankle with China and North Korea, which have been working to improve their own unmanned aircraft fleets.