An illustration of the Chinese and Japanese flags. (Getty Images)

SYDNEY — A Chinese military surveillance PLA Y-9 aircraft “violated” Japanese airspace, prompting Japan to scramble fighters to chase away the spy plane, Japan announced Monday.

The plane was inside Japanese airspace for approximately two minutes at 11:29 am, the Japanese Defense Ministry said in a statement. Many Japanese news outlets, including public broadcaster NHK, are stating that this represents the first time a Chinese military aircraft had violated Japanese airspace.

There are several reasons a surveillance aircraft like the Y-9 may have penetrated Japan’s airspace. One could be to light up its radar and communications systems and gather as much data as possible, something US aircraft did along the Soviet borders during the Cold War. Another could be a political move, essentially signaling a disrespect for territorial boundries.

However, it’s not yet clear the act was premeditated, and China, uncharacteristically, had not issued a statement as of press time.

“I don’t rule out that China did it deliberately, but it is equally possible that the aircraft strayed inadvertently into Japanese air space,” Bonnie Glaser, a top China expert at the German Marshall Fund of the United States, said in an email.

During the incident, Japanese authorities warned the aircraft not to approach. The crew ignored those warnings and continued to patrol just outside Japanese airspace for several hours. Several media outlets in Japan said they had been shown a map showing the plane’s route.

Masataka Okano, Japan’s vice foreign minister, summoned China’s acting ambassador late Monday, and “lodged a firm protest,” with the official, as well as calling for China to ensure it does not happen again, the foreign ministry said in a statement.

A search of past incidents and media coverage from Japan today, indicates China has sent government — not military — aircraft into Japanese territorial airspace two times. Those incursions were into disputed airspace near the Senkaku Islands in the East China Sea.