"When you have a large natural source of wealth discovered in the Atlantic, it's obvious you need the means to protect it," Nelson Jobim said Thursday at a defense conference in Rio de Janeiro.

Jobim said Brazil must safeguard the Tupi field and its 5 billion to 8 billion barrels of oil reserves from other nations and from "actions that could come from the area of terror," the government's Agencia Brasil news service reported.

Brazil has been talking about building a nuclear submarine for decades, but the project got a boost in July when President Luiz Inacio Lula da Silva announced $540 million in funding for uranium enrichment and the sub program.

Jobim said earlier this month that he wants to come up with an outline within three months to build a submarine for about $1.2 billion, the Agencia Estado news service reported. Brazil has no South American enemies and has not experienced terrorist attacks, although U.S. government reports have sporadically raised suspicions that the nation's Triple Border region near Argentina and Paraguay is a fundraising source for radical Islamic groups such as Hezbollah and Hamas.

The Brazilian navy's nuclear program, begun in 1979, has already mastered part of the uranium enrichment process. But it lags in developing and constructing a submarine reactor entirely from Brazilian technology.

Silva has frequently touted nuclear power as a way to diversify energy sources and meet growing demand in South America's largest nation and economy. His government moved in June to restart work on a long-planned third nuclear power plant that has been stalled since the 1980s by lack of funds.

Jobim on Thursday ridiculed the idea that Brazil's uranium enrichment program would ever be used to make a nuclear bomb. "That's total nonsense," he said.