Norwegian energy firm Statoil found more gas offshore Tanzania, its third discovery in the country this year, putting it closer to having the resource needed to make commercial development viable.

Statoil and partner ExxonMobil found more gas in the Lavani prospect when work to deepen a well encountered a separate and "significant" gas reservoir.

Statoil would not release an estimate for the find but said it was "promising" and new figures would be revealed in 2013.

Statoil earlier said it already found around 9 trillion cubic feet of gas in the area and would need roughly another 3 tcf to make commercial development viable.

Mr Nick Maden Statoil's senior vice president for international exploration said that "The Lavani-2 is the third well in an ambitious drilling campaign of four wells within one year. The next well will be the appraisal of the Zafarani discovery."

Analysts earlier predicted that the development could cost the license roughly USD 10 billion.

The discovery confirms East Africa's status as one of the world's fastest growing gas hubs, with the US Geological Survey estimating that 441 tcf of gas may lie off Kenya, Tanzania, Mozambique, Madagascar and the Seychelles, relatively close to Asia's lucrative LNG markets.