Updated

Two children swept away by the Tijuana River south of the border last week remained missing Sunday, after a search for a reported body near storm-swollen waters in San Diego County turned up nothing, authorities said.

Migrants near Border Field State Park reported they may have seen a body in the water early Sunday, said Maurice Luque, a spokesman for the San Diego Fire-Rescue Department. Fire crews assisted by lifeguards and U.S. Customs and Border Protection searched the area for several hours but found nothing.

A 2-year-old girl and a 5-year-old boy were caught in the north-flowing river in Tijuana after a car crash Wednesday and have not been seen since, Luque said.

Mexican authorities said the family's car crashed into the water, killing their 9-year-old sister, according to Luque. The children's parents were also in the car but their conditions were unknown, Luque said.

Authorities said last week's storms caused the dam upstream to nearly crest and that there is a large amount of water flowing through the area. The Tijuana River empties into the ocean just north of the border.