May Day in Costa Rica brought together protesters from public workers unions and a wide variety of other groups, including students, sex workers and indigenous people.
Members of 68 public- and private-sector unions will demonstrate Thursday to mark Labor Day along some San José's main streets, the National Association of Public and Private Employees said.
A small group of demonstrators hurled rocks at the Legislative Assembly building, police officers and members of the national media. At least 20 people were arrested.