Medical staff walk among RV campers at a beachside parking lot being used as an isolation zone for people with COVID-19, at Dockweiler State Beach in Los Angeles, California. Robyn Beck/AFP

WASHINGTON: The US government raced to build hundreds of makeshift hospitals to ease the strain on overwhelmed healthcare systems as the United States marked 700 deaths in a single day from COVID-19 for the first time on Tuesday (Mar 31).