SAN ANTONIO, Texas — U.S. Border Patrol agents on the Southwest border took more people into custody Monday than in any day in the past 10 years, according to U.S. Customs and Border Protection.

Federal law enforcement agents made more than 3,700 apprehensions across California, Arizona, New Mexico, and Texas on Monday.

#BorderPatrol recorded more than 3,700 apprehensions along the Southwest Border yesterday—the largest single day total in more than a decade. pic.twitter.com/JqazvQtoGI — CBP (@CBP) March 27, 2019

A senior Border Patrol official told the Washington Examiner on Tuesday 1,100 of those apprehensions took place in Eagle Pass, Texas, which is part of the Del Rio Sector.

CBP Chief Operating Officer John Sanders told attendees of the Border Security Expo this week a major reason for the recent surge in border apprehensions is due to large numbers of people illegally crossing together, rather than a handful at a time.

In fiscal 2017, CBP documented two groups of 100 people or more. The number of group apprehensions jumped to 13 in 2018 and have spiked to 93 just in the first six months of fiscal 2019.

Sanders said CBP is on track to have taken 100,000 people into custody at the U.S.-Mexico border the month of March. More than one-third of that number is expected to be children.