A U.S. Navy vessel mistakenly emitted unauthorized radio waves on Oct. 17, disrupting an aircraft guidance system at Tokyo's Haneda airport and causing delays to commercial flights, the U.S. forces said Friday.
The vessel is forward-deployed at the Yokosuka naval base in Kanagawa Prefecture.
The U.S. military meanwhile denied any responsibility for two other disruptions on Oct. 21 and 25.
The type of the vessel was not immediately known.
On Oct. 17, radio signals disrupted the approach radar system for one of Haneda's runways, and the glitch forced aircraft to abort instrument landings.
On Oct. 21, radio waves disrupted air navigation facilities in eastern Japan and radio equipment at Haneda was also affected.
On Oct. 25, radio interference temporarily disrupted a channel that air traffic controllers use to communicate with planes departing Haneda airport.
The Ministry of Land, Infrastructure and Transport had asked the Defense Agency and U.S. Forces Japan to investigate.
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