Click on the map to read about the world's trade blocs
The United States has linked with Canada and Mexico to form a free trade zone, the North American Free Trade Agreement (NAFTA).
The NAFTA agreement covers environmental and labour issues as well as trade and investment, but US unions and environmental groups argue that the safeguards are too weak.
The USA hopes to expand the area to the rest of Latin America creating a Free Trade Area of the Americas (FTAA) by 2005, but key countries like Brazil are sceptical of its benefits.
The US is separately signing free trade agreements with Chile and the five central American countries of Honduras, Nicaragua, El Salvador, Panama, and Costa Rica.
Meanwhile, the regional free trade pact called Mercosur, between Brazil, Argentina, Uruguay, and Paraguay, has been put under severe strain because of currency devaluation first by Brazil, then by Argentina.