US and Ally Navies Flex Muscles on 'China's Doorstep'

U.S. and Japanese naval forces on Thursday concluded four days of joint exercises involving multiple aircraft carriers this week in waters Beijing considers to be its "doorstep," as China's navy observed from a distance.

The dozen warships and their complements of aircraft "flew and sailed in accordance with international law in international waters while conducting air defense drills, sea surveillance, cross-deck exercises and tactical maneuvers to advance unique high-end warfighting capability," the participating U.S. carrier groups said in a statement.

The event came just a week after the U.S., Japan, India, and Australia concluded this year's Sea Dragon exercise, centered on anti-submarine warfare. There's a renewed focus on military interoperability among Washington and its allies in the region amid North Korea's ballistic missile tests and China's territorial feuds with Japan and the Philippines over the Senkaku Islands and South China Sea, respectively.

Nimitz-class supercarriers the USS Carl Vinson (CSG-1) and USS Theodore Roosevelt (CSG-9) joined the Hyuga-class helicopter carrier the JS Ise and nine supporting ships in the Philippine Sea.

Washington and Tokyo, which share a mutual defense treaty, are "uniquely capable of rapidly assembling multiple large-deck naval forces in support of mutual security interests in the Indo Pacific," the U.S. Navy said quoted Carl Vinson strike group commander Rear Adm. Carlos Sardiello as saying.

He pointed out such exercises are nothing new, with the Carl Vinson having last joined similar drills along with the Ronald Regan and Japan's de facto navy in November.

In one of the photos released this week by the U.S. Navy, Chinese ship can be seen shadowing the bilateral drills from a few miles away.

Although these exercises take place on a regular basis, Beijing is sensitive to Western military activity in adjacent seas.

China has repeatedly the U.S. and its partners of stirring up trouble at its "doorstep ," and over the past year, Chinese fighter jets have allegedly engaged in unsafe maneuvers while intercepting U.S. and allied planes, putting both sides at risk. Last fall, the Pentagon declassifying evidence of nearly 200 such encounters.

Newsweek reached out to the U.S. Seventh Fleet and Chinese Ministry of Foreign Affairs with written requests for comment.

As of Wednesday, the ships were situated southeast of the Miyako Strait and west of Taiwan, according to ship tracking data reported by Chinese think tank South China Sea Probing Initiative.

"The CSG-1 and CSG-9 are currently deployed to U.S. 7th Fleet area of operations in support of a free and open Indo-Pacific," read a joint statement from the two strike forces.

The presence of the Theodore Roosevelt and Carl Vinson brings the number of U.S. supercarriers in the West Pacific to three, including the forward-deployed USS Ronald Reagan , and the flat top count to four including amphibious assault ship the USS America .

Meanwhile, the Ronald Reagan is at dock at its home port of Yokosuka, Japan , after returning in November from a six-month patrol.

The Navy announced last April the ship would be relocated to Puget Sound Naval Shipyard in Bremerton, Washington, for maintenance at some point this year. The USS George Washington is set to take its place at forward-deployed Seventh Fleet's resident supercarrier.