Singapore: A Chinese spy plane breached Japanese airspace on Monday, the first known incursion of its kind, prompting Tokyo to scramble its fighter jets in response.

The Chinese Y-9 intelligence-gathering aircraft entered Japanese airspace for two minutes from 11.29am near the Danjo Islands, off the southernmost main island of Kyushu, the Japanese Defence Ministry said.

“In response, the Self-Defence Forces scrambled fighter jets from the Western Air Defence Force and took other measures, including issuing notifications and warnings,” the ministry said in a statement.

The airspace breach was “not only a serious violation of Japan’s sovereignty but it also threatens our security”, Chief Cabinet Secretary Yoshimasa Hayashi told reporters on Tuesday.

The government continued to monitor increasing Chinese military activity near Japan and would be fully prepared for any airspace violation, Hayashi said, while declining to comment on the details of the diplomatic talks between Tokyo and Beijing.

On Monday evening, Japan lodged a formal protest with the Chinese government, summoning the Charge d’Affaires of the Chinese embassy in Tokyo, Shi Ying, to a meeting to “strongly urge that the recurrence of this incident be prevented”.

“In response, the Chinese side said they would report the matter to their home country,” a statement from Japan’s Ministry of Foreign Affairs said.

China is yet to publicly respond to the incident.

A flight path published by the Defence Ministry showed the plane circled the area near the Danjo Islands before entering Japanese airspace, and then headed back towards the Chinese mainland. The Danjo Islands are a small uninhabited Japanese island group in the East China Sea, close to the border of what China claims as its exclusive economic zone.