Southern California has been struck by its strongest earthquake in two decades, causing damage and fires.
The epicentre of the 6.4 magnitude tremor was near the city of Ridgecrest, which is about 150 miles (240 km) north-east of Los Angeles.
Firefighters provided medical assistance and dealt with fires in and around the city on Friday.
People from the Mojave Desert to the Pacific coast reported feeling the quake, which hit on Independence Day.
There was significant damage in Ridgecrest, which lies south-west of the epicentre, local geophysicist Professor John Rundle told the BBC.
He added that it was fortunate the had quake happened far away from major population centres.
The Ridgecrest Regional Hospital was evacuated, the Kern County Fire Department said. The service has responded to nearly two dozen incidents ranging from medical assistance for minor injuries to fires.
Brad Alexander, a spokesman for California Governor’s Office of Emergency Services, said on Friday that fire engines and search and rescue teams were going to assist in the Ridgecrest area, where he believed there were a number of buildings on fire.
“This may not be over. There could be more earthquakes happening in the area and anyone listening that’s in that region should be prepared to drop cover and hold on,” he warned.
The city’s mayor, Peggy Breeden, told CNN that a state of emergency has also been declared in the city.
Ms Breeden said that some people had been struck by objects falling from buildings and gas lines had been broken.
“We are used to earthquakes but we’re not used to this significance,” she said.
Stephen Sykes, who lives in Ridgecrest, was in the shower when his house started to shake.
“The whole house shook violently and we both ran out into the street. This went on for about 10 to 15 seconds, we were really scared,” he told the BBC.
“Currently we are getting ready in case there’s another one. We are moving items onto the floor and have turned off the gas supply. We will probably sleep outside tonight,” he added.
The earthquake was reportedly felt as far as Las Vegas in Nevada. There have been several smaller aftershocks.
President Donald Trump tweeted that the situation was under control.
Lucy Jones, a seismologist with the US Geological Survey, told reporters the epicentre was in a relatively uninhabited area.
She said there would likely be a number of aftershocks, some powerful.
One man tweeted images from inside a supermarket in Ridgecrest, which has a population of about 28,000 people, showing the aisle floors covered with fallen items.