From breitbart.com:

Dozens of “caravan migrants” camped out near the San Ysidro Port of Entry on Sunday night after being turned back by U.S. Customs and Border Protection (CBP). U.S. officials told the migrants their processing facilities were full and they would let them know when they could cross at a later date.

“At this time, we have reached capacity at the San Ysidro port of entry for CBP officers to be able to bring additional persons traveling without appropriate entry documentation into the port of entry for processing, CBP Commissioner Kevin McAleenan said in a written statement obtained by Breitbart Texas. “Depending upon port circumstances at the time of arrival, those individuals may need to wait in Mexico as CBP officers work to process those already within our facilities.”

http://www.breitbart.com/texas/2018/04/30/caravan-migrants-stalled-border-crossing-checkpoint/