Updated at 7.20pm: Police issued a warning on Friday to traders selling mobile phones of unknown origin. The warning came after three men were fined in Kwun Tong Magistracy earlier this month for selling mobile phones without licences. On October 11 police officers launched a nine-day joint operation with the Office of the Telecommunications Authority to investigate the sale of unlicensed mobile phones. 640 mobile phones were reported lost in the Kowloon East region this year, and police believe the lost phones might have been sold to unlicensed traders. 32 locations were raided, and 67 mobile phones seized. Eight men and a woman were arrested for selling mobile phones without a licence. Under the Telecommunications Ordinance, those who trade without a licence are liable to a fine of $50,000 and two years' imprisonment on summary conviction, or a fine of $100,000 and five years' imprisonment on conviction on indictment.