Bulgaria's Supreme Administrative Court said it has closed a case against a decision by the country's anti-trust regulator to reinstate Saudi-led consortium Arkad as winner in a tender for construction of a leg of TurkStream gas pipeline.The Supreme Administrative Court has dismissed the case as one of the participants in the consortium which filed the appeal, the Bulgarian branch of Luxembourg-registered Completions Development, has withdrawn its complaint against the regulator's decision, the court said in a statement on Monday. In order for the court to carry on with the legal proceedings, all participants in the consortium, which besides Completions Development comprises Italy's Consorzio Varna 1, should agree on the complaint, the court explained.The court's decision can be challenged before a five-member bench of the Supreme Administrative Court within seven days.Bulgarian gas transmission operator Bulgatransgaz named Arkad group as winner of its tender for construction of a 484 km pipeline for transit of gas from the border with Turkey to the border with Serbia but subsequently dropped its original choice and chose as winner the second-ranked consortium.The contracting authority said it had revised its decision because Arkad had failed to present the required documents and sign the contract. In July Bulgaria's competition regulator cancelled Bulgartransgaz' decision to disqualify the original winner and said that the gas transmission operator had been unlawfully holding parallel talks with the Consorzio Varna 1 - Completions Development consortium after ranking the Arkad group first in the tender. Subsequently, the second-ranked consortium offered a price discount for the construction of the pipeline in violation of legal requirements, the regulator said at the time.Arkad had proposed to build the pipeline for 1.29 billion euro ($1.42 billion) within 250 days, or for 1.10 billion euro within 615 days. The Consorzio Varna 1 - Completions Development group initially offered to build the pipeline for 2.41 billion euro and 1.60 billion euro, respectively, but subsequently lowered its offer for the 615-day period to 1.10 billion euro.The court also backed the competition watchdog's decision regarding the urgency of the tender procedure. Bulgartransgaz claimed that the procedure is of great importance for Bulgaria's economy and therefore must not be halted but the regulator said those claims were unfounded.At the end of January, Bulgartransgaz successfully completed the binding Phase 3 of the economic test for the pipeline project - part of a larger project of Russia's Gazprom to build a string of its TurkStream pipeline for transit of gas to Europe from Turkey via Bulgaria, Serbia and Hungary.The offshore section of the TurkStream pipeline stretching 930 km across the Black Sea from Russia to Turkey consists of two parallel strings with annual throughput capacity of 15.75 billion cubic metres of gas each. One string is intended for consumers in Turkey, while the second will carry gas to customers in Europe through Bulgaria.