The US-Mexico border has been rocked by a 5.7-magnitude earthquake that rattled nerves in a region still recovering from the deadly Easter tremor, seismologists said today.

A strong earthquake south of the US-Mexico border swayed high-rise buildings in Los Angeles and San Diego and was felt across Southern California and Arizona.

Inmates at a maximum security prison in southern California jumped guards in the prison yard, sparking a riot that left one inmate dead and at least 30 inmates and 20 guards wounded.