A magnitude-6.4 earthquake hit 12 kilometers southwest of Searles Valley in the U.S. state of California at 17:33 GMT on Thursday, the U.S. Geological Survey (USGS) said. According to local authorities, it was the strongest earthquake to rock the region since 1999. 

The quake was detected at a depth of 8.68 kilometers. There are no reports of casualties so far.

The tremors were felt across the Los Angeles region on Thursday morning, as local residents said on social media that they felt the shakes and steady sways, some of which lasted for almost 30 seconds.

U.S. President Donald Trump tweeted: "All seems to be very much under control."

But damages and fires have been reported near the city of Ridgecrest, southwest of the epicenter and some 175 kilometers northeast of Los Angeles.

The Kern County Fire Department said on Twitter it was working on "nearly two dozen incidents ranging from medical assistance to structure fires in and around the city of Ridgecrest, CA."

Ridgecrest Mayor Peggy Breedon also said the city was dealing with fires and broken gas lines, as well as falling objects that have hit people, as the city endured aftershocks.

(With input from agencies)