United States President Donald Trump on Thursday said the situation in Southern California, which was rattled by a 6.4-magnitude earthquake, was under control. The earthquake, said to be the strongest one in the region in almost 20 years, was centred near the city of Ridgecrest, 150 miles [nearly 241 km] from Los Angeles.

“Been fully briefed on earthquake in Southern California,” Trump tweeted. “All seems to be very much under control!”

The earthquake caused at least 159 aftershocks of 2.5 magnitude or higher, CNN quoted United States Geological Survey Seismologist Robert Graves as saying. The strongest aftershock was 4.6 magnitude.

“The earthquake was centered in the Searles Valley area located approximately 160 miles outside of Los Angeles and at this time, there are not any reports of serious damage to city infrastructure, nor have any injuries been reported in Los Angeles,” the Los Angeles Police Department tweeted.

Ridgecrest Mayor Peggy Breeden said that the city had announced a state of emergency. “As I understand, we have five fires,” she said. “We have broken gas lines.” At least 28,000 residents faced power cuts as temperatures rose to 100 degrees Fahrenheit [approximately 38 degrees Celsius]. Evacuations were done at the Ridgecrest Regional Hospital and about 15 patients were shifted from the emergency room to another hospital.

Seismologist Dr Lucy Jones warned of more aftershocks as she predicted that a magnitude 5 aftershock was likely.

The earthquake broke water mains, disrupted power lines, caused cracks in buildings in San Bernardino County, officials said, according to ABC News.

No injuries were reported in Los Angeles and Mayor Eric Garcetti said that no significant damage had been reported. “@LAFD has completed their surveys of @LACity and reported no significant #earthquake damage from today’s quake near Ridgecrest,” he tweeted. “City agencies are working together and staying on alert. Be prepared, sign up for emergency alerts.”