China’s top spy agency on Monday warned air passengers against opening window shades during take-off and landing to take photos at dual civil-military use airports after a foreigner was found snapping pictures from a mobile phone, according to a media report.

The Ministry of State Security in a post on its official WeChat account, akin X, urged passengers to comply with instructions to close window shades during take-off, landing and taxiing at dual airports.

They must not take unauthorised photos or videos, or upload the content online, it said, noting that the practice was “in line with the standard approach of countries worldwide to maintain secrecy around military facilities”, the Hong Kong-based South China Morning Post reported.

The ministry said the warning was issued in reference to a recent case involving a foreigner, but did not give further details.

According to domestic media reports, a foreign national on board a flight from the eastern Chinese city Yiwu to Beijing earlier this month allegedly used a mobile phone to take photos of a joint-use airport, and a fellow passenger reported the issue following which the local officials alerted the police.

“Safeguarding national security is the responsibility and duty of every citizen. Unauthorised filming of military facilities and equipment poses a serious threat to national security,” the ministry said, while also calling on the public to cooperate in maintaining the security and confidentiality of joint-use airports.

In the post on WeChat, the ministry said joint-use facilities which make up nearly one-third of China’s airports, usually deploy important military equipment and passengers are not permitted to take photos of the sensitive military areas.

These airports are used for both civil aviation and regular air force training, and will be available for military use during wartime, the ministry said. Also, many of them are located near coastal and border areas “holding prominent strategic positions and significant military value”, it noted.

China in recent months stepped up the public and security of its military installations amid its intensified strategic rivalry with the US and its allies especially over the disputed South China Sea and Taiwan.

While China claims most of the South China Sea as its own, it also asserts that the self-ruled Taiwan island as part of the mainland and vows to take over it.

The Philippines, Vietnam, Malaysia, Brunei and Taiwan have counterclaims over the South China Sea.

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