London, Jun 26 (IANS): New evidence of China's 'spy' balloon programme - including flights over Japan and Taiwan has been uncovered, media reports said.

Japan has confirmed balloons have flown over its territory and said it's prepared to shoot them down in future, BBC reported.

US-China relations were thrown into turmoil earlier this year, when an alleged Chinese spy balloon was shot down off the US coast.

China claimed the balloon seen over north-western US in late January was a civilian airship, used for scientific research such as meteorology - and that it was an unintended and isolated event.

John Culver - a former East Asia analyst for the CIA - told BBC Panorama that this "had been not just a one-off, but a continuing effort dating back at least five years."

He said the Chinese balloons were "specially designed for these long-range missions" and some had "apparently circumnavigated the globe".

Working with Synthetaic, an artificial intelligence company which sifted through huge amounts of data captured by satellites, the BBC has found multiple images of balloons crossing East Asia.

The company's founder, Corey Jaskolski, found evidence of one balloon crossing northern Japan in early September 2021. These images have not been published before.

Jaskolski also believes the evidence points to this balloon having been launched from deep inside China, south of Mongolia, BBC reported.

Japan is a close ally of the US and more American forces are stationed there than in any other foreign country.