Vietnam Post and Telecommunications (VNPT) has submitted a plan to the Ministry of Post and Telematics (MPT) to reduce mobile phone tariffs charged by its subsidiaries MobiFone and VinaPhone. The two GSM operators are planning a 25% fee reduction in addition to changes to charge structures: call duration will be calculated by blocks of 15 or 20 seconds, instead of the current 30 seconds. Competitors Viettel and S-Fone already calculate charges in blocks of six and ten seconds respectively.