A Mexican army convoy crossed the Rio Grande into the Texas Thursday bringing aid to victims of Hurricane Katrina.
The unit headed for San Antonio is the first Mexican military operation on U.S. soil since 1846.
The convoy crossed the Rio Grande near Laredo Thursday morning, carrying water treatment plants, mobile kitchens and supplies to feed victims of Hurricane Katrina.
The 45 green vehicles displaying Mexican flags and about 200 personnel will apparently be used to provide water, meals and other help for hurricane survivors from the New Orleans area.
Mexican officials said they have another land convoy and another ship preparing to help.
The convoy and a Mexican naval mission arriving near New Orleans are the first Mexican military presence on U.S. soil since 1846. That's when Mexican troops briefly marched into territory disputed between the two countries along the border of Texas.
Texas had separated from Mexico and joined the United States in 1836.