SEOUL, South Korea, July 7 — Samsung Electronics, the world’s third largest maker of mobile phones, has banned the use of camera phones in some of its factories, fearing they could be tools of industrial espionage. The decision is an embarrassing admission by the South Korean company of the potential misuse of one its fastest-growing products....

“Use of camera phones will be restricted in our most sensitive plants such as research and development centers and semiconductor labs,” Samsung said.

Camera phones have become part of everyday life in South Korea and Japan, the world’s most advanced wireless markets, with people using the devices to e-mail photographs to friends and family.

But as use of camera phones has become more widespread, so too has concern about possible criminal use of the tiny camera lenses in mobile phones. Camera phones look like normal handsets. A user could take a photo of a person or a place without anybody knowing and immediately distribute it via the internet.

Security experts have warned that camera phones could be used by criminals or terrorists to monitor individuals or sensitive buildings, while the devices could be used at concerts or other entertainment events in violation of copyright. Governments in several countries have also expressed fears about their use by pornographers.

J-Phone, the Japanese wireless operator, has responded to the concerns by making its camera phones emit a noise to alert people when a picture is being taken.

Samsung has chosen a low-technology remedy. It said people would be allowed to bring camera phones into its factories if lenses were covered with a plastic sticker.

Samsung has overtaken Siemens and Sony Ericsson to take third place in the global ranking of handset makers, behind Motorola and Nokia, the market leader.