While Lieutenant-Colonel Lori Hodge, spokesman for the Pacific Air Forces, did not give further information on the exact manoeuvres carried out by the Chinese jets, CNN reported earlier that the jets came within 46m of a US Air Force plane flying over the Yellow Sea.
The case constituted "airspace incursion" for Japan, Inada added. "This will allow us to continue building confidence with our Chinese counterparts on expected maneuvering to avoid mishaps".
Mid-air interceptions occur routinely in worldwide airspace, but the United States military will often call out foreign pilots if it judges the maneuvers to be risky or unprofessional. "This flight was no exception".
Unexpected and unsafe intercepts involving USA and Chinese military aircraft have occurred occasionally over the South China Sea, which China claims virtually in its entirety.
The two countries are at odds over a group of small uninhabited islands in the East China Sea, administered as the Senkakus by Japan but claimed as the Diaoyus by China.More news: 5 things to know about French president-elect Emmanuel Macron
The Air-Self Defense Force scrambled two F-15 fighter jets in response to the deployment of the drone around the Japanese-controlled islands, claimed by China.
"This is a new form of activity by China", he added.
In recent years, the sides have signed a pair of agreements aimed at preventing such encounters from sparking an global crisis, as happened in April 2001 when a Chinese jet fighter collided with a U.S. surveillance plane over the South China Sea, leading to the death of the Chinese pilot and China's detention of the 24 USA crew members for 10 days.
Japan air force scrambled fighter jets to shadow Beijing's movement in the disputed islets in the East China Sea on Thursday (18 May) after four Chinese coastguard vessels entered contested waters administered by Japan.
Japanese Defense Minister Tomomi Inada on Friday criticized an apparent drone flight linked to a Chinese government vessel that entered Japanese waters around the disputed islands in the East China Sea the previous day, describing it as "a violation of sovereignty".More news: Samsung Galaxy J7 2017 Spotted on GFXBench With Two 12MP Cameras
The move prompted an outcry from Japan and the United States, but a U.S. report previous year suggested that it was not being fully enforced.
The director-general of the Japanese Foreign Ministry's Asian and Oceanian Affairs Bureau, Kenji Kanasugi, made a stern protest over the incident to the Chinese Embassy in Tokyo by phone, according to Reuters, citing ministry officials.
This is the first time we see what appears to be a drone flown by Chinese ships that are sailing within territorial waters. It was the first such intrusion into Japanese waters by Chinese government ships since May 8, and the 13th this year.
"This is not a military action as has been hyped up by some media", Hua told a daily news briefing.
The plan sparked massive anti-Japanese protests across China, and Chinese Coastguard vessels and fishing boats began plying waters around the islands.More news: WannaCry Ransomware: Microsoft Calls Out NSA For 'Stockpiling' Vulnerabilities