Republicans are also looking into accusations that the immigration service falsified figures to make its enforcement operation along the California-Mexico border look more effective than it is.

A proposed reservoir just north of the California-Mexico border would correct an inefficient water delivery system that allows excess water to pass to Mexico.

Such is the volume of traffic over the California-Mexico border that United States customs agents cannot begin to catch shippers of dangerous materials.

Since a fence was erected in 1994 covering parts of the California-Mexico border, around 3,000 people have died trying to cross into southern Arizona.

Complaining about drug-related violence created by "third-world people," he advocates building a wall across the California-Mexico border.

The California-Mexico border has never been a safe place.

"This is the most elaborate and sophisticated tunnel that has ever been discovered along the California-Mexico border," special agent Benner said.

Controversy over the California-Mexico border and California Proposition 187 had strained the relationship between the two parties.

The California-Mexico border is the most popular crossing for undocumented aliens, whether by car or on foot.

Since 1994, the U.S. government has been building a fence along parts of the California-Mexico border, though that fence still isn't finished.