TAIPEI (Taiwan News) — A U.S. Air Force reconnaissance aircraft has flown directly into the East China Sea area of China’s air defense identification zone (ADIZ).

Chinese think tank South China Sea Strategic Situation Probing Initiative tweeted that a U.S. Air Force RC-135U aircraft had entered China’s ADIZ Thursday morning (June 3). The plane took off from Kadena base in Okinawa, Japan, and flew into the East China Sea before heading west towards China. It then turned south and flew as far as Fujian Province before returning to the base along the same flight path.

Multiple American military planes have conducted missions in the region in the past two days. On Wednesday (June 2), a U.S. Navy P-8A maritime patrol aircraft flew southward along the median line of the Taiwan Strait, the Liberty Times reported.

The same day, two U.S. Marine Corps V-22 tiltrotor planes and two MC-130 special operations command aircraft were spotted in the Bashi Channel between Taiwan and the Philippines. Southwest of the channel, two RC-130 reconnaissance planes, a KC-135 tanker aircraft, and a P-8A patrol plane were detected.

The RC-135U is a reconnaissance aircraft manned by a minimum of 21 crewmembers that is capable of locating and identifying military ground, ocean, or air-based radar signals as well as collecting data for further analysis.