Albania\'s competition authority has started a preliminary investigation against three mobile operators for allegedly fixing the tariff for the pre-paid cellular phone packages. A decision made available Wednesday said the three unnamed providers had changed their tariffs for pre-paid users by means of \"a prohibited agreement.\" It said the three providers that make-up 95 percent of the Albanian market were operating in an oligopolistic manner \"to abuse with their dominating position.\" A report from the preliminary probe is expected in three months. Albania has high mobile phone usage. There are 5.3 million subscriptions in a population of just 3 million for its four cellular providers — Vodafone Albania, Telekom Albania, Albtelecom Mobile and Plus Communication. Around 90 percent of the market is pre-paid.   Source: Association Press