RWE of Germany and Gaz de France, two of Europe's biggest energy companies, are interested in taking a stake in the proposed Nabucco pipeline to bring gas from the Caspian region to the European Union, in a signal that progress on the long-mooted project is at last gaining momentum.

A decision about accepting at least one extra member into the Nabucco consortium, led by OMV of Austria, is expected to be taken by the end of next month.