Libya's rebels in April promised France 35% of the country's crude oil in exchange for supporting the Transitional National Council in its fight against Muammar Gaddafi, a French newspaper reported.

Liberation newspaper published a copy of a letter in Arabic from the Popular Front for the Liberation of Libya, the forerunner to the rebels' council, addressed to Qatar, in which the rebels apparently refer to a deal to give 35 per cent of Libya's crude to France in return for supporting the rebellion.

The letter, which was dated April 3, two weeks after the start of the military intervention in support of the rebels that France had championed, said the deal was struck with France "during the London summit".

An international conference on the conflict in Libya was held in London on March 29.

France's foreign ministry told Liberation it had no knowledge of the existence of the letter.

A TNC representative was not immediately available to confirm the existence of such a letter.

French oil giant Total is one of several players in the Libyan oil market. The biggest oil producer in Libya is Italy's Eni.

Eni and Total have been tipped to emerge as the biggest winners in the post-Gaddafi era, given the strong support shown by their countries for the rebels.