The Antimonopoly Committee of Ukraine has opened a case against joint-stock company Kyivstar and private joint-stock company MTS Ukraine, as the companies have failed to observe recommendations on domestic mobile communications tariffs, reads a committee report issued on September 27, 2012.

The committee said that the operators did not fulfill the committee's recommendations to cut tariffs to an economically justifiable level.

"An analysis of the information on the fulfillment of the committee's recommendations submitted by the operators did not confirm that there had been a reduction of the prices of the said services," the committee said.

The committee also noted that there had been a rise in the prices of some services.

The committee recommended that the operators reduce the price of mobile communications services in June 2012.

The committee is also investigating the roaming tariffs of the operators.