MOL officials told Bloomberg News it didn't approve of the pipeline's budget for 2012 "because of the uncertain costs and gas sources and with the current structure and project management the implementation of the Nabucco project is not secured."
Hungarian Prime Minister Viktor Orban said from Brussels this week that MOL had decided to walk away from the $10.4 billion pipeline project. He made the comments during talks with European officials in Brussels. The European Commission had rejected a request from Hungary for a financial bailout because of concerns over Orban's grip on power, Bloomberg reports.
Nabucco is part of a series of gas transit networks outlined in the Southern Corridor, a group of European pipeline networks meant to break Russia's grip on the regional energy sector.
Hungary gets about 80 percent of its natural gas from Russia and the government recently backed up South Stream, Russia's counterpart to Nabucco.
Officials from the Nabucco group said there was no formal indication MOL left the pipeline consortium. Marlene Holzner, a spokeswoman for the European Union, told Bloomberg the Nabucco pipeline agreement was with the Hungarian government and not MOL.