During a training drill, Customs and Border Protection officials block the entrance to the San Ysidro port of entry Thursday,…
FILE - During a drill, Customs and Border Protection officials block the entrance to the San Ysidro Port of Entry, Jan. 10, 2019, as seen from Tijuana, Mexico.

U.S. border protection officials in San Diego said Friday that 20 people had been rescued from flooded drainage pipes west of the San Ysidro Port of Entry. 

A Border Patrol agent found three people trying to enter the United States illegally late Thursday near a drainage tube about 3 kilometers west of the port of entry, according to U.S. Customs and Border Protection, the Border Patrol's parent agency.

In a release, CBP said the three people told agents there were people trapped inside the drainage tubes, with water rising because of heavy rain in the area. 

After a search, local emergency officials aided CBP agents in recovering 17 people, sending seven of them to a nearby hospital for medical care.

About an hour later, three more people were discovered in the drainage tubes and were taken into custody. One was sent to the hospital.

CBP said it apprehended 15 men, three women and one juvenile male from Mexico, and one Guatemalan man. It said all would be processed for illegally entering the United States.