Border Patrol agents detaining a group of undocumented aliens last Monday night near the US-Mexico border were fired upon by attackers presumed to have been on the Mexican side of the border.

According to a statement from the US Customs and Border Protection agency, on August 9 at around 9pm, the agents were seizing a group of migrants near Otay Mountain in San Diego County, California.

The agents were "approximately two miles east of the Otay Mesa gatehouse and approximately 250 yards north of the international border," according to the report, which was originally published in Spanish.