The terrorist attacks in the US have forced Secretary of State Mr Colin Powell to cut short his Latin American trip.
But before he left to return to Washington, he told the Organisation of American States foreign ministers in Peru, that "they will never be allowed to kill the spirit of democracy".
The ministers were meeting to approve an agreement setting democratic standards for all 34 active OAS member nations.
Mr Powell said: "You can be sure that America will deal with this tragedy in a way that brings those responsible to justice.
"You can be sure that as terrible a day as this is for us, we will get through it because we are a strong nation, a nation that believes in itself."
Aboard his plane later, Mr Powell called the attack "a well-coordinated extensive assault against the United States".
He said he wouldn't speculate about who was behind the attacks, adding: "There has been no reputable claim of responsibility that's been made yet."
AP