DUBAI // The telecoms operator du has successfully blocked almost 20,000 fake handsets from using its network. All of the unauthorised phones - 18,118 of them - have now been banned from accessing the company's mobile service. The firm said it had enforced the restriction in accordance with a directive from the Telecommunications Regulatory Authority (TRA) to block invalid 15-digit International Mobile Equipment Identity (IMEI) numbers. The ban came into force on January 1. The devices affected were 17,416 consumer phones and 702 enterprise or business handsets. "We are pleased to announce that as of January 24 we have successfully blocked all handsets using an invalid IMEI," said du. "We would like to thank our customers for their cooperation during this process." The company said it would continue to monitor and block any fake IMEI numbers using its network. In the run-up to the ban, the TRA ran newspaper advertisements warning people of the new rules. Federal authorities imposed the restrictions because many of the handsets with counterfeit IMEIs are made using substandard materials. As a result, the phones are prone to have faults such as leaking batteries and are even deemed to be a fire hazard. Du said at the beginning of the month that the campaign to raise awareness before the ban came into force had been a success, with the number of reported fake IMEI numbers falling from 57,338 to 17,797.