MEXICO CITY—A 4-year-old Honduran boy was found traveling alone near the Rio Grande River that separates Mexico from the United States with no one to claim him, the Mexican government said on Wednesday. Mexico’s National Migration Institute (INM) said the boy was found unaccompanied among trees and thickets as he walked toward the border. He was close to Reynosa, a Mexican city long troubled by violence, that sits across from McAllen, Texas. A group of three mothers and six children were located in the same area, but none of the adults took responsibility for the boy or acknowledged him as a relative, the INM said. The migrants, all Hondurans, were detained when a flyover of the area spotted a group of women and children running and ducking for cover in grasslands and trees, the institute said. The boy, who was not named, is one of the thousands of children to …