The mayor of Tijuana, Mexico, declared an international humanitarian crisis Thursday for his city after about 5,000 Central American migrants traveling in a caravan descended on the U.S. border.

Mayor Juan Manuel Gastelum made a public appeal during a Thursday press conference for help from the United Nations in the absence of adequate assistance from the Mexican government and his reluctance to allocate his city’s own public resources to counter issues created by the sudden influx of people, according to the Associated Press.