Seoul,  South Korea's National Intelligence Service (NIS) on Monday formally raised an alarm about the possibility of cou.

The NIS made public a photo of a fake bill, similar to a so-called supernote in its highly deceptive characteristics, which it had acquired recently, reports Yonhap News Agency.

"Such a $50 counterfeit has not yet been found in South Korea, but it is continuing to circulate in Asia," it said.

The NIS plans to share relevant information with related authorities, including the Bank of Korea and the Korea Customs Service.

An NIS official said: "Chances are high that it will flow into South Korea due to increased demand for foreign currency on the occasion of the Beijing Olympics in February next year."