Chinese mobile service operator China Unicom (CHU) has begun another round of sanctions against wireless value-added service providers (WVAS).

It has punished some of the service providers who failed to fulfill its requirement by screening their value-added services and is asking others that have not met the criteria to rectify themselves before May 25.

WVASs that have been notified by China Unicom this time include Sohu.com (SOHU), Tencent and Tom.com (TOMO).

China Unicom has conducted a spot check on service providers' charging patterns, requiring them to provide free downloads and trial use of services for their WAP, graphics, music and ringtones.

China Unicom requires the service providers to submit a rectification report before May 25, otherwise their services will be terminated by May 30.