By The Associated Press

Federal officials are boosting efforts at Arizona national monuments to prevent what they say is a path of destruction left by illegal immigrants crossing from Mexico.

The Arizona Republic reports that the U.S. Bureau of Land Management has recruited more than a dozen rangers from other states in the last several months to patrol two Southern Arizona monuments.

Authorities say operations are focused on the Sonoran Desert National Monument, south of Phoenix, and the Ironwood Forest National Monument, north of Tucson.

The BLM says both sites draw drug smugglers and illegal immigrants because of their remote locations and possible hiding places. They say illegal immigrants have left acres of trash and abandoned cars.

Conservation groups have criticized the BLM for putting up steel barriers that they say ruin the landscape.