Los Angeles is offering free coronavirus tests to all residents, regardless of whether they are displaying any symptoms.
Mayor Eric Garcetti made the announcement just hours after Los Angeles County reported its largest daily increase in new Covid-19 cases.
Until now, only essential workers and those displaying symptoms could receive tests due to a scarcity of kits.
Meanwhile, California ordered all beaches in Orange County to close.
California is the most populous state in the US, and while some of its beaches have been closed for weeks, others have remained open with social distancing rules in place.
Over the weekend, photos of crowded beaches in the county, which is south of Los Angeles, led state governor Gavin Newsom to warn that the behaviour of some sun-seekers threatened to undo weeks of work to restrict the spread of Covid-19.
What’s going on in Los Angeles?
Los Angeles County currently accounts for almost half of California’s confirmed coronavirus cases. The state has so far reported over 48,000 cases and more than 1,900 deaths.
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On Thursday, Mr Garcetti urged all of the city’s residents to get swabbed after earlier tweeting that “LA is now the first major city in America to offer free Covid-19 testing”.