Two Mexican environmentalists have been freed after they were briefly kidnapped by settlers seeking to carve up North America's last large pocket of tropical rain forest, their group said Tuesday. AP reported the kidnapping follows the two-day abduction and subsequent release of a former federal environment secretary in a different part of the jungle a month ago, amid a battle over the governance and land use in the 1,290-square-mile (330,000-hectare) Montes Azules - Blue Mountains - forest reserve in the southern state of Chiapas, near the Guatemalan border. The head of the Na Bolom Cultural Association, Maria Luisa Armendariz, said two of the association's activists and two American tourists driving with them were stopped at a roadblock inside the Lacandon jungle by settlers. Maria Luisa Armendariz said Tuesday the settlers surrounded the vehicle Sunday and threatened to burn it or tip it over. They allowed the vehicle and its occupants to leave unharmed on Monday, about 20 hours later. "They were rocking the truck, saying they were going to tip it over," Armendariz said. "The threat was that they were going to set it on fire."