French President Francois Hollande's visit to Brazil next month for the Rio+20 summit could help hasten Brasilia's decision on a contract to buy 36 next-generation fighter jets, a government official said Wednesday.

The Rafale fighter, made by French firm Dassault Aviation, is competing against the US F/A-18 Super Hornet and Swedish manufacturer Saab's Gripen for the contract valued at between $4 billion and $7 billion.

The government official, speaking on condition of anonymity, said Hollande's attendance at the June 20-22 UN summit on sustainable development "could untie the knot", with Brasilia hoping for clarifications on the French offer.

"We are not happy with any of the proposals" right now, the official said, explaining that the French price was deemed too high while Brasilia does not trust US assurances on technology transfer.

Brazil, Latin America's dominant power and the world's sixth-largest economy, is insisting on technology transfer in all its defense agreements.

Last month, US Defense Secretary Leon Panetta visited Brazil and pledged US advanced technology transfers if Brasilia chooses the Boeing's F/A-18.

France has offered full technology transfers in its bid to win the contract.

Another factor is India's recent tentative decision to buy 126 Rafales in a contract valued at $12 billion, a more attractive price than that proposed to Brazil.

Brazilian Defense Minister Celso Amorim traveled to India in February to discuss prospects for a "technical military accord."