WASHINGTON — The defense chiefs of the United States and Brazil signed a military agreement aimed at strengthening cooperation in training, defense technology and promoting exchanges of visits by naval ships.Officials for both countries emphasized the deal does not entail US military bases or the presence of its troops on Brazilian soil. That is an apparent nod to the negative reaction from the region's leftist governments to a pact between Colombia and Washington that allows US access to Colombian military bases.US Defense Secretary Robert Gates and Brazilian Defense Minister Nelson Jobim signed the deal Monday ahead of a nuclear summit. Gates heads to South America later this week.When reporters asked Jobim about the possible US purchase of up to 100 Super Tucano built by Empresa Brasileira de Aeronautica SA, the official said that the accord will "help" with these negotiations but that a decision has yet to be made.As for the F-18s that Brazil might buy from Chicago-based Boeing, Jobim said that he will make a decision this month or in May.At a press conference at the Brazilian Ambassador's residency in Washington, Jobim highlighted that the military agreement does not violate Brazil's sovereignty and the principle of no intervention. In the days previous to the signing, there was speculation that the agreement could be similar to the one the US signed with Colombia to increase its military personnel in the South American country. Venezuela and other countries strongly condemned the accord with Bogota. After the meeting, Gates said the agreement was a "formal acknowledgement of the many security interests and values we share" and was a "positive model for engagement throughout the Americas", according to a Department of Defense transcript. "This agreement will lead to a deepening of US-Brazil defense cooperation at all levels and will demonstrate how much more effectively we can confront shared security challenges when we work in partnership", said the secretary. According to Jobim, he also talked about Iran's nuclear program with Gates. Jobim said he reiterated Brazil's position regarding Teheran. The Brazilian government believes that imposing new sanctions will lead to the country's radicalization. The minister warned that in Iraq's case, they did little to stop Saddam Hussein. "The decisions we make, have to be intelligent decisions." said Jobim.