TAIPEI (Taiwan News) — The National Communications Commission said Wednesday it is partnering with major mobile operators to introduce voice alerts for hidden-number calls.

Chunghwa Telecom network branch head Teng Chung-ching (鄧忠清) said users answering hidden-number calls will hear a seven-second alert first, per CNA. The message includes a Mandarin and Taiwanese warning: “This is a hidden-number call, please be cautious.”

Users will not be charged for the alert, Teng explained. They can press any key to skip the message.

The alert is enabled by default and users can check its status for free by dialing 12165. Government agencies may apply for a whitelist so the alert does not play.

NCC Secretary-General Huang Wen-che (黃文哲) said scammers often spoof international or local numbers, tricking users with calls starting with “+886” or “+.” Previous blocking and alert measures have reduced these calls, but scammers are now using hidden numbers.

Such calls now account for about 10% of calls, Huang noted, per The Storm. Data from the National Police Agency showed 99.6% of hidden-number scam victims are mobile users.

Chunghwa Telecom will pilot the system on March 2, followed by Taiwan Mobile in April and Far EasTone in May.