A Marine based in California was arrested Monday by Customs and Border Protection officials for allegedly smuggling undocumented immigrants into the United States, according to the Marine Corps.

The smuggling took place at the San Ysidro Port of Entry, the 1st Marine Division told NBC News in a statement.

The Marine, who had just finished entry-level training, is currently being held in civilian custody and was not part of the military support mission at the Southwest border, according to the statement. The Marine was not identified.

The border crossing between California and Tijuana, Mexico, is the largest point of entry in the United States and sees tens of thousands of people pass through on a daily basis.

This isn’t the first time in recent months Marines from Camp Pendleton, where the 1st Marine Division is based, have been detained on suspicion of human trafficking. The Marine Corps said of the 23 Marines detained in July from three separate incidents involving human trafficking, drug distribution and weapons charges, six have pleaded guilty to charges at court-martials.

Thirteen of them have agreed to leave the Marines and the rest are in the "process of being adjudicated" according to the statement.

Officials said there appears to be no connection between Monday's arrest and the other incidents involving Marines from Camp Pendleton.

CORRECTION (Dec. 4, 2019, 7:51 a.m.): A previous version of this article misspelled the Marine base. It is Camp Pendleton, not Pendelton.