Six of the nearly two dozen Marines accused of participating in human and drug trafficking rings have pleaded guilty, the government confirmed Tuesday.

Twenty-three Marines were detained in July 2019 for alleged human trafficking, drug distribution, and weapons charge, according to the 1st Marine Division, which is based at Marine Corps Base Camp Pendleton.

In a brief update Tuesday afternoon, the 1st Marine Division confirmed six Marines have pleaded guilty to charges during court-martials.

The department said 13 of the remaining 17 Marines requested separation from service instead of undergoing courts-martial. All 13 of their pre-trial requests were approved.

The final four Marines are being reviewed by officials for their alleged crimes.

On July 3, 2019, U.S. Border Patrol agents reportedly spotted three undocumented immigrants jump into their car on Interstate 8, just north of the border near Tecate.

A federal complaint alleged the undocumented immigrants told Border Patrol they had agreed to pay the Marines $8,000 to take them north from the border to Los Angeles, eventually intending to head to New Jersey.

Afterward, Border Patrol made its first arrests in the case: Lance Cpl. Byron D. Law and Lance Cpl. David J. Salazar-Quintero. Law and Salazar-Quintero were the only two named defendants at the time.

On July 25, 2019, 16 Marines, all E-2 to E-4 in rank, were arrested during a battalion formation, which consists of about 800 Marines at Camp Pendleton. The following day, investigators confirmed a Navy sailor and two other Marines were also arrested. Several were released.

The 1st Marine Division did not provided further updates about the 23 Marines Tuesday.

More than 42,000 active duty personnel work on Marine Corps Base Camp Pendleton.

The base, located on the coast near Oceanside, California, also hosts thousands of Marine reservists for annual training on its firing ranges, Urban Terrain facilities and training areas.