Bulgaria's anti-monopoly watchdog said Thursday that it had raided the offices of the country's three foreign-owned electricity distributors as part of a probe for suspected infringements of competition rules.
The commission for the protection of competition said in a statement that Czech utilities CEZ and Energo-Pro and Austrian EVN are suspected of "applying identical practices with the aim to hinder the change of electricity suppliers by consumers."
The commission will aim to establish if these market practices are coordinated, it added.
The probe had been agreed with the European Union, which will assist Bulgaria in the probe.
Bulgaria vowed this week to perform a thorough review of its troubled energy sector after massive protests against high electricity bills helped topple the government in late February.
Bulgaria's caretaker prime minister Marin Raykov asked the EU on Wednesday to assist the country in its efforts to reform the sector as sanctions from Brussels loomed for Sofia's failure to open the energy market.
In an attempt to appease angry consumers, Bulgaria's energy watchdog has launched procedures to revoke CEZ's distribution licence and agreed to cut regulated electricity prices for households.