Coronavirus infections have risen by a third in North America over the past week due to surges in the US and Canada, the Pan American Health Organisation says.
Hospitals in the Canadian province of Alberta are facing critical staffing shortages, according to the PAHO, the regional branch of the World Health Organisation.
The United States is reporting more than 100,000 new daily infections for the first time since January and hospital capacity in many southern US states remains worryingly low, the agency said.
As many parts of the world report a steady decrease in coronavirus infections, the Americas reported a nearly 20 per cent increase in new cases, the PAHO said.
Most South American countries are recording continuing declines in COVID-19 cases and deaths, it said.
Infections are surging in Costa Rica, Guatemala and Belize and many hospitals there are saturated with COVID-19 patients.
Meanwhile, infections have slowed in the Caribbean, with the exception of Grenada, Barbados and Bermuda that are reporting sharp rises in new cases, and Jamaica has registered its highest weekly case count since the beginning of the pandemic.
"We are encouraged that more than 30 per cent of the people in Latin America and the Caribbean have been fully vaccinated against COVID-19," PAHO Director Carissa Etienne said in a weekly briefing.
But she said doses have not been equally distributed in the region and there is still a long way to go to reach everyone who needs a vaccine.
Australian Associated Press