Tens of thousands of Costa Ricans, some dressed as skeletons and holding banners, protested on Sunday against a US trade pact they say will flood the country with cheap farm goods and cause big job losses.
Chanting "No to the free-trade pact!" and "Costa Rica is not for sale!" protesters ranging from farmers to housewives filled one of San Jose's main boulevards to demonstrate against the Central American Free Trade Agreement with the United States.
Costa Rica is the only country that has not ratified CAFTA - which includes Guatemala, El Salvador, Honduras, Nicaragua and the Dominican Republic - and will be on October 7 the only nation to decide the issue by referendum.
The referendum has split the nation, with Costa Rican President Oscar Arias and some businesses saying CAFTA will bring investment and jobs. Opponents say it will mean a flood of cheap agricultural imports and limit the country's sovereignty by taking investment disputes to international arbitration.
"The trade deal is putting at risk our workers' rights. We need an accord with the United States, but not this way," said Juan Chacon, a 50-year-old computer technician.
A poll last week by the daily La Nacion showed the "yes" side ahead in the referendum by a slim 50.6 percent to 44.7 percent margin with a 3.8 point margin of error.