BP, Total, Eni and other international majors were awarded concessions to explore in Angola's ultra-deep water blocks known as pre-salt blocks, Angola's state-owned oil firm Sonangol said on Monday.

Other successful bidders included ConocoPhillips, Statoil, Repsol and Cobalt International Energy.

A total of 13 companies participated in the tender which was never officially announced.

Angola, which rivals Nigeria as the top oil producer in Africa, awarded concessions to the oil companies across 11 blocks, with each holding different stakes and some acting as operator. Sonangol said it would participate in each one of the blocks.

Angola said last year it was keen to develop its pre-salt blocks. This could bring huge profits for Angola which has similar underwater rock formations to Brazil, which in 2007 made a pre-salt discovery of some 8 billion barrels of crude in its Tupi field.

This was Angola's first offshore bidding round since 2007. The country suspended a round in 2008 before the country's first post-war general elections.