BRASILIA (Reuters) – The number of people infected with the coronavirus in the Americas is fast approaching 4 million with almost 204,000 deaths, and the pandemic continues to accelerate, World Health Organization (WHO) regional director Carissa Etienne said on Tuesday.

Speaking in a virtual briefing from Washington-based Pan American Health Organization (PAHO), Etienne said COVID-19 has hit the region’s migrants particularly hard.

There should be stepped up testing in the U.S-Mexico border area due to unconfirmed reports of increasing numbers of people infected with the virus in the United States arriving there to travel to Mexico, PAHO recommended.

The regional wing of the WHO has sent teams to enhance surveillance and testing in Haiti’s frontier with the Dominican Republic due to surging cross-border transmission.

Chile, which took aggressive steps from the start of the outbreak to curb the spread of the virus, has seen growing cases in the last two weeks, leading to reinforced social distancing measures for all its territory, PAHO’s assistant director Jarbas Barbosa said.

The onset of winter in South America has PAHO worried that serious cases of COVID-19 will rise further.

Brazil, which has the world’s second worst outbreak after the United States, is a major concern for the regional health body. Coronavirus-related deaths are surging in Brazil, even as the government of President Jair Bolsonaro encourages resumption of economic activities.

Brazil accounts for 23% of the more than 3.8 million coronavirus cases in the Americas and 23% of the almost 204,000 deaths, Etienne said. “We are not seeing transmission slowing down” in Brazil, she said.

PAHO recommends that Brazil and other countries in the region continue strengthening social distancing and urged reopening of the economy be done slowly and carefully.

“The epidemic has still not passed its peak in Latin America and mitigation measures should continue,” said PAHO Communicable Diseases director Marcos Espinal.