Mexico and Haiti have detected coronavirus infections among migrants deported recently from the United States, officials said on Tuesday, part of a growing trend of contagion among deportees

The new infections come after an outbreak among deportees to Guatemala, where the government at the weekend linked almost a fifth of all cases of the new coronavirus in the country to flights returning migrants from the United States last week.

All three affected countries have far fewer confirmed cases of the disease than the United States.

Three Haitians who arrived in the Caribbean country two weeks ago tested positive while in quarantine, a Health Ministry official told Reuters. The flight had raised objections from human rights advocates worried about exporting the virus to the Western Hemisphere’s poorest country.

In the Mexican border town of Nuevo Laredo, one man deported from Houston infected 14 others at the Catholic church’s Nazareth migration shelter, state authorities and the city’s bishop said. Cubans, Mexicans, Hondurans and a migrant from Cameroon were among those who caught the virus, officials said. The 15 who tested positive, who include three children 16 years old and under, have been placed in isolation, shelter authorities said.

It is not clear where the deportees contracted the virus, but the new cases led to calls for deportations to be suspended unless U.S. authorities can test migrants before they leave the country.

Workers at some U.S. deportation and migrant detention facilities have tested positive for the virus, U.S. Immigrations and Customs Enforcement has said.

Rachel Schmidtke, Refugees International’s advocate for Latin America, said that while the source of the infections was still not known, keeping migrants in crowded detention centers increased the risk of contracting the virus.

“Nobody should be deported unless they have been tested and they test negatively for Covid-19,” Schmidtke said.

Haiti so far only has 57 confirmed cases of COVID-19. Haiti’s prime minister, Joseph Jouthe, said another flight carrying more than 100 Haitian deportees was expected this week.