"I don't think America gets enough credit for trying to help improve people's lives," Bush said at a joint news conference with Brazilian President Luiz Inacio Lula da Silva. "My trip is to explain as clearly as I can that our nation is generous and compassionate."
Bush shrugged off fresh attacks from Chavez, his primary South American tormentor. The Venezuelan leader is staging a tour of the region to rival Bush's weeklong, five-country visit.
On Friday, in Buenos Aires, Argentina -- about 1,000 miles southwest of here -- Chavez called Bush's travels an attempt to divide and confuse Latin American nations.
"The future belongs to us," Chavez told reporters, adding "Oh, ho ho! Gringo go home!"
(MAURILIO CHELI ~ Associated Press)
Chavez is using his country's vast oil wealth to reach out to ordinary Latin Americans and to court other leftist leaders.
Asked directly about Chavez's latest taunts, Bush refused to mention Chavez by name, a common practice. "I bring the good will of the United States to South America and Central America," he said. "That's why I'm here."
Bush noted total U.S. aid has doubled since he took office to $1.6 billion last year. Some Latin American critics say Bush's claim is misleading because it is based on using 2001 as the starting point, and U.S. aid had dipped sharply that year, setting an artificially low benchmark.
The Bush administration sees the leftist Silva as a counterbalance to Chavez for influence in the region. As a sign of his standing, the president has invited Silva to visit the presidential retreat at Camp David, Md., on March 31.
The centerpiece of Bush's Brazilian stop -- the first before he headed on to Uruguay, Colombia, Guatemala and Mexico -- was a new ethanol development agreement.
The two went in the morning to a large fuel depot for tanker trucks, the backdrop for arguments from Bush and Silva that increasing alternative fuel use will lead to more jobs, a cleaner environment and greater independence from the whims of the oil market. In Brazil, nearly eight in 10 new cars already run on fuel made from sugar cane.
The agreement, signed Friday morning by Secretary of State Condoleezza Rice and her Brazilian counterpart, has the United States and Brazil joining forces to promote more ethanol use in nations lying between Brazil and the United States. It also creates new quality standards for the alternative fuel.
But there were clear remaining tensions on a related issue: the 54-cent-a-gallon U.S. tariff on imports of Brazilian ethanol made from sugar, a measure designed to help U.S. corn growers. Corn can be made from either crop.
Before Bush's visit, Silva said the tariff was unfair and that he would press Bush to try to get the U.S. Congress to repeal it.
"It's not going to happen. The law doesn't end until 2009. And the Congress will ... look at it when the law ends," Bush said tersely during their news conference.
For his part, Silva joked about the impasse and his inability to change Bush's mind.
"If I had that capacity for persuasion that you think I might have, who knows? I might have convinced President Bush to do so many other things that I couldn't even mention here."
"This is a process," the Brazilian president added.
Bush and Silva also agreed to try to relaunch stalled global trade talks -- the so-called Doha round -- and Bush said, "We will work together. We will lock our trade ministers in a room, all aimed at advancing this important round."
U.S. Trade Representative Susan Schwab was staying behind to meet with Brazilian officials on Saturday morning.
Brazil is the largest economy in Latin America.
Protests to Bush's visit on Friday weren't as large or as violent as the day before.
About 150 protesters gathered outside Bush's hotel, burning an effigy of the American president with a swastika on his shirt and a Hitler mustache.
The protesters chanted, "Bush go home," and held up banners decrying American imperialism before a phalanx of military police while Bush and Silva ate lunch and talked to reporters inside.
Later, a crowd of onlookers waved as Bush and his wife, Laura, arrived for a chat with teens at a community center computer lab. But on the way out, a group of about 15 youngsters cursed Bush, calling him "assassin" and saying "go home." Bush waved and smiled, and other onlookers waved back and took photos.
Students in Sao Paulo also went into a McDonald's and gave bananas to customers. Lucia Kluck Stumpf, director international relations for the National Students Union said the stunt was to "peacefully eat bananas to show that we are not a banana republic." And about 200 Brazilian students chanting anti-Bush slogans marched to the American Embassy in the capital of Brasilia, where they unfurled Cuban and Venezuelan flags. It was not violent.
On Thursday, before Bush's arrival, police here used tear gas and batons against some in a crowd of more than 6,000 who were protesting Bush's visit and policies.