Algeria, Nigeria, Niger sign memorandum for Sahara gas pipeline
The three countries had in June agreed to revive the decades-old talks over the project, a potential opportunity for Europe to diversify its gas sources.
The pipeline is expected to span 4,000 kilometers (2,485 miles), according to Algeria's Ennahar TV.
The Trans-Saharan gas pipeline is an estimated $13 billion project that could send up to 30 billion cubic metres a year of supplies to Europe.
The idea was first proposed more than 40 years ago and an agreement signed between the countries in 2009, but progress stalled.