A Chinese military aircraft was confirmed for the first time to have violated Japanese territorial airspace on Monday morning, the Defense Ministry in Tokyo said, with Japan strongly protesting the move.

The Defense Ministry said one of the Chinese military's Y-9 intelligence-gathering planes had briefly entered Japanese territory near the Danjo Islands off Nagasaki Prefecture from around 11:29 a.m. to 11:31 a.m., prompting the Air Self-Defense Force to scramble fighter jets in response.

The ministry said the fighters had taken steps such as "issuing warnings," while NHK reported that no weapons or flares were fired.

According to a map of the flight path provided by the Defense Ministry, the Chinese plane continued to circle in an area near the Danjo Islands for some time after leaving Japanese airspace.

At around 5:20 p.m., Japan's vice minister for foreign affairs, Masataka Okano, summoned the charge d'affaires of the Chinese Embassy in Tokyo to the Foreign Ministry to deliver a solemn protest and "strongly request" that the Chinese side prevent any recurrence, the ministry said in a statement.

In response, the Chinese side said that it "would report the matter to their home country."

Underscoring the unprecedented nature of the move, China is believed to have previously sent government aircraft into Japanese territorial airspace on just two occasions, both of which, unlike Monday's incursion, involved contested territory.

Both instances — once in 2012, when a propeller plane was detected, and another time in 2017 with a small drone — occurred near the Japanese-controlled Senkaku Islands in the East China Sea. China also claims the islands, which it calls the Diaoyu.

Beijing routinely sends military aircraft into international airspace above the East China Sea and elsewhere around Japan, but this is the first instance of a territorial airspace violation by a Chinese military aircraft to be publicly confirmed by Tokyo.

Observers say the moves are intended to probe Japan's response time and erode the capabilities of its fighter jets.