President Bush's attendance at the Summit of the Americas triggered violent protests in Mar Del Plata, Argentina, the site of the summit.
Tens of thousands of demonstrators paraded through the streets on Friday calling for Americans to get out of Iraq and Afghanistan, and for the moment, out of Argentina.
Mr. Bush was to attend more meetings before flying to Brazil, and on to Panama.
Bush's domestic political troubles seemed to follow him on his trip. In a session with reporters, several questions were asked about the CIA leak investigation back home, and whether his top political adviser, Karl Rove, might step down. Rove hasn't been indicted, but he remains under investigation. Mr. Bush declined to discuss Rove's future.