SAN ANTONIO (Reuters) - Texas Governor Rick Perry on Friday ordered the Texas National Guard to search for the bodies of undocumented immigrants who have died by the hundreds in a remote part of the state as they attempted to walk to southern cities hundreds of miles (km) away.

The guard troops have been deployed to Brooks County, a rural area about 120 miles (190 km) north of the Texas border with Mexico, to search for the corpses of undocumented immigrants who died trying to walk through the desolate region known as the "Brush Country," in hopes of reaching San Antonio or Houston.

"For many years, law enforcement and landowners in this area have been overwhelmed by the tragic impacts of human smuggling across our county," Brooks County Sheriff Rey Rodriguez said.

Smuggling gangs who bring undocumented immigrants into Texas frequently stop in Brooks County before they reach an immigration checkpoint in the community, according to border control agents.

The smugglers kick the immigrants, including the elderly, pregnant women, and families with infants, out of their trucks and tell them that Houston, 200 mikes (320 km) away, is a few hours by foot, according to agents.

Ranchers find the bodies of the undocumented immigrants with disturbing regularity after they die in the rugged conditions where summertime temperatures frequently exceed 110 degrees Fahrenheit (43 Celsius).

Rodriguez said that since 2011, 332 sets of human remains have been found in Brooks County alone and the bodies of hundreds or thousands more are believed to lie in the barren countryside.

Officials did not say how many troops would be deployed. They will begin work immediately in groups of 20 to 25, scouring areas where authorities expect to find bodies.

Areas where bodies are found will be treated as crime scenes and the Texas Rangers will be called when necessary.

Local officials during the summer investigated a portion of a pauper's cemetery in Brooks County where more than a dozen bodies, believed to be those of undocumented immigrants, were found buried in trash bags or tossed in groups into graves.

(Reporting by Jim Forsyth; Editing by Brendan O'Brien and Sandra Maler)