August 9 (SeeNews) - Slovenian energy company Petrol [LJE:PETG] said on Tuesday it plans to invest between 25 million and 30 million euro ($35.6-42.7 million) in establishing a network of some 12 to 14 state-of-the-art service stations in Montenegro. The Slovenian company also said in a bourse filing it has raised to 100% from 50% its stake in Montenegrin company Petrol-Bonus. The takeover follows the signing of a buyout agreement with the other Petrol Bonus shareholder, Montenegro Bonus, the statement said. The deal enables Petrol to expand the network of service stations operating under its brand name in Montenegro, president of the Petrol managing board, Tomaz Berlocnik, said in the statement. At the end of June 2011, Petrol Group operated three filling stations in Montenegro. "The signing of the agreement means that the rights and obligations of Petrol arising from the [2007] Petrol - Bonus establishment agreement are terminated, with the two parties now set to focus on their core business activities. Petrol will henceforth operate independently in Montenegro," the Slovenian company said. In 2007, Montenegrin state-owned oil firm Montenegro Bonus and Petrol signed an agreement to set up a joint oil and gas storage venture. The joint venture, Petrol Bonus, was designed to build and operate oil and gas storage facilities in Montenegro as well as build at least 20 filling stations within five years. Montenegrin daily Vijesti (www.vijesti.me) reported Montenegro Bosnus and Petrol officials as saying on Monday that the initial joint venture contract signed in 2007 was overly ambitious and therefore unworkable.