Border Security Gaps Worry U.S. Officials

The U.S. government has become increasingly concerned that al Qaeda might try to exploit security gaps at the nation's borders, especially the Mexican border, ABC News has learned.

Concerns about border security were highlighted on July 19, when officials at McAllen-Miller International Airport in southern Texas arrested a woman suspected of having ties to al Qaeda.

Farida Goolam Mohamed, who had an airplane ticket to New York, was stopped when a Border Patrol agent noticed several pages of her South African passport had been removed. Officials also said her clothing was dirty and muddy, suggesting she might have recently crossed the nearby Rio Grande, the river separating Mexico and Texas.

The arrest is one reason why U.S. officials are increasingly concerned al Qaeda may try to smuggle terrorists into the United States from Mexico.

"Al Qaeda has recognized that one of our vulnerabilities is our [in]ability to completely seal and control access through Mexico," said ABC News consultant Jerry Hauer, former director of New York City's Office of Emergency Management.

Border Crossings Are Vulnerable, Experts Say

The 2,000-mile-long border with Mexico is virtually impossible to defend, officials said. And sources tell ABC News there is new intelligence that al Qaeda wants to smuggle terrorists across it.

It's well known that many Central Americans have been illegally coming across the U.S.-Mexican border. Now the U.S. government estimates that a quarter-million illegal aliens — not only from Central America, but also Africa and the Middle East — have been coming across the southern border each year.

Last month, customs officers at Miami's airport arrested an Egyptian national on charges of smuggling people from the Middle East through Central America into Mexico, and then into the United States.

"It's easy for anyone, including a terrorist who really wants to get into the United States to do so by crossing the Mexican or Canadian border," said ABC News consultant Richard Clarke, former chief of antiterrorism in the Bush and Clinton administrations.

Since Sept. 11, 2001, the U.S. has been trying to improve security at both borders with unmanned surveillance aircraft, increased vehicle searches and X-ray devices that scan vehicles for hidden illegal weapons or people.

Along the U.S.-Canada border in the woods of Vermont, sensors hidden in the ground trigger surveillance cameras that zero in on anyone trying to enter the United States illegally.

But it may be impossible to fully police the more than 5,000 miles of U.S. border with Canada and Mexico.