Japanese officials say unidentified flying objects spotted in the country's airspace in recent years are strongly suspected to have been Chinese spy balloons.

The Defense Ministry announced their analysis on Tuesday.

Balloon-like objects were spotted over Japan's territory at least three times between 2019 and 2021.

Officials urged Beijing to confirm details and prevent the recurrence of such incidents.

They told their counterparts that violation of airspace by foreign spy balloons cannot be tolerated.

Defense Ministry sources say the analysis is based on intelligence from the United States about the Chinese balloon the US military shot down on February 4.

Beijing claims it was a "civilian airship" mainly used for weather research.

The US also downed three unidentified flying objects over North America this month.

China responded by claiming that high-altitude balloons from the US have flown through its airspace without permission more than 10 times since the start of 2022.

Washington denies the allegation.