Presidents George W. Bush of the US and Luiz Inácio Lula da Silva of Brazil yesterday signed a green fuels agreement that promises co-operation on technology and development but fails to address the central issue of access to the US market for Brazilian producers.

Mr Bush was in São Paulo on the first stage of a five-nation tour of Latin America. The initiative is one of a number designed to restore US credibility in a region increasingly under the sway of "21st century socialism" led by Hugo Chávez, president of Venezuela.