A higher administrative court in Bulgaria upheld on Wednesday a lower court's decision to annul the ban on an oil refinery belonging to Russian oil giant LUKoil, the Novinite.com agency said. The Bulgarian customs earlier withdrew a license from the LUKoil Neftochim Burgas, the largest oil refinery in southeastern Europe, for allegedly failing to properly monitor the movement of oil products, which helps prevent any possible tax evasion. A court later ruled that Bulgaria's largest enterprise could resume work, but customs appealed the decision. The higher court upheld the ruling, saying a halt in the oil refinery's operations would cause serious economic damage. The oil refinery has contracts with local transportation companies and is the sole producer of aviation fuel on the Balkans. The Bulgarian authorities were forced to unlock their strategic reserves of aviation fuel when the plant suspended its operations. This court decision will allow the oil refinery to run until the end of the year, when LUKoil has promised to install the required equipment, according to Bulgarian Prime Minister Boyko Borisov, who has also criticized the company for alleged violations.