A powerful earthquake of magnitude 6.4 struck Southern California near the city of Ridgecrest, about 113 miles (175km) northeast of Los Angeles, the US Geological Survey said on Thursday.

The Kern County Fire Department said on Twitter it was working “nearly 2 dozens incidents ranging from medical assistance to structure fires in and around the city of Ridgecrest, CA.”

Ridgecrest Mayor Peggy Breedon told CNN that things were falling off buildings and hitting people and the city had felt several aftershocks.

She added there were fires and broken gas lines.

“We are used to earthquakes but we're not used to this significance,” she said. The city has asked residents to look after others, especially the elderly, which forms a large part of her city's population.

She said she had felt many quakes before but “not one like this long rolling” temblor, she told CNN, adding she was driving in her car when it happened and immediately pulled up her emergency brake.

The USGS said the quake, initially reported as a magnitude 6.6, was very shallow — only 5.4 miles (8.7km) - which would have amplified its effect.

The temblor, which struck at around 1:30pm EDT in an area on the edge of Death Valley National Park, was felt throughout Los Angeles, as far north as Fresno and as far east as Las Vegas, Nevada. It was even felt south of the border in Mexico, where buildings were evacuated in the towns of Tijuana and Mexicali, according to Baja State officials.

According to European quake agency EMSC, the quake was felt in an area inhabited by some 20 million people.

The epicentre was very close to Ridgecrest, a town with a population of more than 27,600 in the high desert. The area is associated with the Eastern California Shear Zone and has suffered earthquake swarms in the past, including a series of some 2,500 tremors over the course of five weeks in the summer of 1995.

Thursday's quake was quickly followed by many smaller aftershocks in the area.

USGS seismologist Lucy Jones said on CNN the area would be hit by many more aftershocks in the coming days, and could even be hit by a larger quake.

A magnitude 6.4 quake is considered strong and is capable of causing severe damage.

Thursday's quake is the largest in Southern California since 1994 magnitude 6.6 Northridge earthquake, which was centered in a heavily populated area of Los Angeles and caused billions of dollars of damage.