Marco Aurelio Garcia, foreign policy adviser to Brazilian President Luiz Inacio Lula da Silva, said Brazil was examining ways to cooperate with Venezuela in the nuclear field.

"We are studying forms of cooperation in this area, as we have in the oil area," Garcia said during a meeting of Iberian and Latin American leaders.

Garcia's statement appeared to reverse previous statements by Brazil's government, which said earlier this year no nuclear cooperation with Venezuela was under consideration.

Venezuela, the world's No. 5 oil exporter, is a top supplier of crude to the United States but left-wing leader Chavez frequently clashes with Washington, which is worried over his strong links to Cuba's Fidel Castro.

Garcia said there was no reason to fear cooperation with Venezuela on nuclear energy.

"I see no problem with this as our (nuclear) programmes are completely transparent," Garcia told reporters when asked if such cooperation could worry Washington.

In 2004, Brazil commissioned nuclear enrichment at its Resende plant in Rio De Janeiro -- becoming one of a handful of countries to master the technology to enrich uranium for energy.

Brazilian authorities have guaranteed that their technology would only be used for peaceful purposes -- nuclear weapons are banned under its constitution.

Still, Brazil had a few tense months of negotiations with the International Atomic Energy Agency, centered on whether the agency could have full visual access to the plant.

An Argentine newspaper report last weekend said Venezuela asked Argentina to buy a medium-strength nuclear reactor.

Argentina's Clarin newspaper reported that the request by the Venezuelan government for the reactor was being treated "like a hot potato" by the administration of Argentine President Nestor Kirchner.

Countries that already have nuclear energy should not prevent third world countries developing their own, Chavez said.

Chavez announced in May his intentions to study the use of nuclear power, saying his government could start talks with Iran as well as with Argentina and Brazil.

Energy has been one of the main topics at the summit, attended by oil producers such as Venezuela and Mexico and oil importers suffering from record high oil prices.

Chavez's calls for greater efforts to increase the use of renewable and nuclear energy came after the summit's permanent secretariat announced it would look into ways of using more renewable energy.

Economies in energy-poor Central America have been knocked by high oil prices and the summit's Secretary General Enrique Iglesias said plans were discussed to ease those countries' energy bill.

Mexican President Vicente Fox said on Saturday his country planned to strengthen Central America's energy supply as part of a regional infrastructure plan linking the Mexican state of Puebla with Panama.