Beijing (PTI): A video clip of a couple kissing at a subway station posted on a website has sparked a public debate on privacy and monitoring device, prompting the authorities to launch a probe into the incident. The couple aged around 20 unaware of the camera were captured in a passionate moment at the entrance of a subway in Shanghai and the three-minute clipping found its way into the internet and became a hit.

Shanghai subway authorities said they were investigating whether their staff used the monitoring device and made the video. "If it was really done by workers, the company will seriously deal with those involved and improve interior education and management," sources were quoted as saying by official Xinhua news agency.

The monitoring system had been installed under subway operation regulations, a source from Shanghai Shentong Metro Co Ltd, which runs the subway stop where the video was suspected to have been shot, said.

"The behaviour of the couple at the public venue was somewhat improper, but it was rather embarrassing for the video to be posted on the internet," the agency quoted a Shanghai resident Deng Ke, as saying.

Cameras are widely installed in taxis in some cities such as the southwestern Chonggqing and northeastern Shenyang. "If the situation in the taxis is normal, pictures of passengers will be automatically deleted. It is only when drivers have alerted police will photos be preserved by the system," said Yan Bin, a Shenyang Communications Bureau official.