U.S. Interior Secretary Ryan Zinke is visiting the U.S.-Mexico border in southern Arizona.
Zinke viewed parts of Buenos Aires National Wildlife Refuge on horseback Saturday and plans to tour Organ Pipe Cactus National Monument Sunday.
The refuge and the monument are under Zinke's department and located within the Border Patrol's Tucson Sector, which is a busy crossing point for drug smugglers and migrants entering the United States illegally.
The department's announcement of the trip said Zinke was making an "on-the-ground assessment" of the refuge, which is 56 miles (90.12 kilometers) southwest of Tucson.
Wildlife refuge specialist Josh Smith says Zinke spent about 4 1/2 hours at the refuge, including being driven to a location where he and others got on horses to ride among rolling hills near the border.