A suspected Russian helicopter entered Japan's airspace Tuesday off its northernmost main island of Hokkaido, the Defense Ministry said, adding Tokyo lodged a stern protest with Moscow over the incident through diplomatic channels.

The chopper was observed intruding into the airspace above waters off the Nemuro Peninsula in eastern Hokkaido around 12:44 p.m., with the Air Self-Defense Force scrambling fighter jets in response to the trespass, according to the Japanese ministry.

A similar violation by a suspected Russian helicopter occurred in March 2022 after Japan, along with many Western countries, started to impose economic sanctions on Russia following the start of its aggression against Ukraine the previous month.

Last year's intrusion took place near a group of Tokyo-held, Moscow-claimed islands called the Northern Territories in Japan and the Southern Kurils in Russia.

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