Chinese authorities have warned that South Korean journalists could face an unspecified "stern measure" if they report along the sensitive border between North Korea and China without prior permission, an official at the South Korean Embassy in Beijing said Wednesday.

The warning came less than a week after South Korean journalists reported about activities of trade between North Korea and China in the Chinese border city of Dandong, following a sudden cancellation of a concert in Beijing by a North Korean female band earlier this month.

Chinese authorities have notified the South Korean Embassy that the recent media report was made "without prior permission from a local Chinese government," the official said on the condition of anonymity, citing sensitivity of the issue.

"The Chinese side said it will take stern measures in line with relevant regulations if it detects illegal reporting activities in the future along the border with North Korea," the official said.

China is always sensitive about security of its border with its ally North Korea.

China bans foreign journalists from reporting inside the country without journalist visas and often expels or jails foreign reporters working without proper credentials. (Yonhap)