Japan has accused the Chinese reconnaissance plane of violating Japanese airspace, marking the first such direct incursion.
Japan scrambled fighter jets after a Y-9 maritime patrol plane “violated airspace” over the Tancho Islands for about two minutes at 11:29 local time (02:29 GMT) on Monday.
Japan's chief cabinet secretary called the violations “totally unacceptable” and summoned Chinese embassy officials in Tokyo to protest.
The incident comes amid rising tensions in the region as China competes for influence against the United States and its allies, including Japan.
Japanese broadcaster NHK said Japanese authorities issued “notices and warnings” to the Chinese planes during Monday's incursion but that no weapons such as signal flares were used.
Nonetheless, the incident raised concerns.
The Japanese government said it had contacted Beijing through diplomatic channels to strongly protest the incursion and to demand that such incursions not be made in the future. Beijing has not issued an official response.
Tokyo also recently warned of the presence of Chinese vessels in the Senkaku Islands in the East China Sea, which are claimed by China and called the Diaoyu Islands by Beijing.
The islands, uninhabited but potentially rich in oil and natural gas reserves, are one source of tension between Beijing and its neighbors, most of which are US allies.
The other is the Japanese island of Okinawa, which is home to the largest US military base in the Asia-Pacific region, with US troops also stationed in Taiwan, the Philippines and South Korea.
“China does not tend to directly intrude into Japanese airspace so this incursion may seem alarming,” Prof Ian Cheong, an expert on China foreign policy at the National University of Singapore, told the BBC.
“But this is consistent with China's actions towards Taiwan and the Philippines in recent years.”
Taiwan's Defense Ministry reported last month that in one day alone, Chinese military aircraft crossed the so-called “median line,” the unofficial border on both sides of the Taiwan Strait, 66 times.
Beijing does not recognise the median line, and Taiwan says its aircraft have crossed it hundreds of times over the past two years.
Meanwhile, the Philippines recently called China the “biggest destroyer of peace” in Southeast Asia.
The comments came following a clash on Sunday in a disputed area of the South China Sea that Manila called a resupply mission to fishermen.
“This is a struggle, so we have to expect these actions from China,” Philippine Defense Secretary Gilberto Teodoro said.
“As I have said repeatedly, we must be prepared to expect and become accustomed to these clearly unlawful actions by China,” he told reporters on Monday.
US National Security Advisor Jake Sullivan is in Beijing this week for talks with Chinese Foreign Minister Wang Yi.
The two sides are expected to discuss differences over several issues in the region and around the world.
“Washington will likely consider ways to avoid uncontrollable escalation, but this proposal may be difficult to implement,” Prof Chung said.
Additional reporting from Tokyo by Chika Nakayama
