LOS ANGELES (BNO NEWS) -- A strong earthquake struck southern California on Monday evening and was felt as far away as Los Angeles and San Diego, seismologists said. There were no immediate reports of damage or casualties.

The 5.7-magnitude earthquake at 9.26 p.m. PDT (0426 UTC Tuesday) was centered about 5 miles (8 kilometers) southeast of Ocotillo, a census-designated place in Imperial County near the border with Mexico. It struck about 4.3 miles (6.9 kilometers) deep, making it a shallow earthquake, according to the California Integrated Seismic Network.

The West Coast and Alaska Tsunami Warning Center said no tsunami was expected as a result of the earthquake, which was widely felt in Los Angeles and San Diego. Also some people in western Arizona reported feeling the earthquake, as well as some people in Mexico near the U.S. border.

The strong earthquake was quickly followed by a series of small to moderate aftershocks. At least 32 aftershocks were reported 30 minutes after the initial earthquake, but only 4 of them exceeded 4.0 on the Richter scale.

The strongest aftershock, at 9.59 p.m. PDT (0459 UTC Tuesday), had a preliminary magnitude of 4.0 on the Richter scale.

The Los Angeles Fire Department said it entered an Earthquake Mode as a preventive measure after the earthquake struck. "No damage has been reported yet," said Devin Gales, a spokesman for the Los Angeles Fire Department.

When the Los Angeles Fire Department enters an Earthquake Mode, firefighters are dispatched to check their district for any damage.

Earlier this year, on April 4, a 7.2-magnitude earthquake struck the area, killing at least 2 people and injuring more than 200 in the Mexicali area of Mexico.

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