Costa Rican authorities dismantled on Tuesday a network dedicated to the trafficking of Cuban migrants entering from Panama and intending to reach the United States or Mexico.
Migration from the countries of northern Central America to the United States has been reduced by more than 75% since last May, US interim Secretary of Security Chad Wolf said.
There are currently more than 87,000 applications for refuge in Costa Rica, of which 80% are from Nicaraguans and 7% are from Venezuelans, according to government data.
Many international observers say the country -- with 60 percent poverty -- is in no shape to welcome refugees but simply signed the agreement under intense US pressure.
The UN urged countries Tuesday to take joint responsibility for caring for surging numbers of displaced people, while wealthy nations faced criticism for not shouldering their "fair share" of the burden.
The president of Costa Rica, Carlos Alvarado, will ask the international community for help in the face of an influx of migrants, the government said Sunday.