The Okinawa Prefectural Assembly agreed Tuesday to send a letter to Prime Minister Junichiro Koizumi adamantly calling for Okinawa Cellular Telephone Co. to be exempt from regulations on "dominant" mobile phone operators, despite its dominant share in the prefecture, assembly officials said.

The assembly unanimously reached the agreement ahead of a decision today by the Telecommunications Council, an advisory panel to the telecommunications minister, on whether Okinawa Cellular and nine companies in the NTT DoCoMo Inc. group should be deemed "dominant."

The council is set to make its decision in line with a revision in the Telecommunications Business Law, under which a mobile phone operator with a market share of 25 percent or more is identified as dominant and subject to some business restrictions.

Naha-based Okinawa Cellular, which operates solely in Okinawa Prefecture, has a 49 percent share of that market, but its share nationwide is 0.5 percent.