The U.S. war against terrorism has quickly reshaped relations with both Canada and Mexico. The strong trade link, through the North American Free Trade Agreement (NAFTA), is also becoming a strong security arrangement.

The impact of the terrorist attacks against the United States has been felt south of the border. Armed soldiers can be seen patrolling near the bridges that connect Juarez with the city of El Paso, Texas. Mexican Customs agents are also on the alert for suspicious-looking vehicles.

U.S. Immigration Service agents say there has been excellent cooperation from Mexican officials and from the Mexican consulate in El Paso during this time of heightened alert.

Mexico's Interior Minister, Santiago Creel, says steps are being taken to prevent terrorists from operating from Mexico. He says Mexican authorities are reinforcing the nation's intelligence, law enforcement and immigration measures. He says he wants to keep his nation calm, and that there is no evidence so far that Mexico is at risk.

In the days after the September 11 attacks, Mexican authorities detained dozens of people of Central Asian or Middle Eastern origin, but Mr. Creel says no one is currently being held in connection with the terrorist acts.

Mexican army troops remain on the southern border to prevent the entry of undocumented people from other nations who may wish to transit Mexico on the way to the United States. There is also extra security around Mexico's oil fields and refineries.

Mexico supplies the United States with 1.5 million barrels of oil each day.

U.S. officials increasingly see Mexico and Canada as the rear guard for protecting the United States. A report conducted in late September by a private firm called Strategic Forecasting says security will become the major issue in the relations between the three nations.

The report predicted that the United States, Canada and Mexico would work to form a North American security perimeter, with counter-terrorism being the priority.