At least eight other Marines have also been questioned about their involvement in alleged drug offenses.

July 25, 2019, 2:16 PM EDT / Updated July 25, 2019, 3:05 PM EDTBy Doha Madani and Courtney Kube

Sixteen U.S. Marines were arrested Thursday on human smuggling and drug allegations at a base in Southern California, military officials said.

The Marines were arrested at Camp Pendleton based on information gained from a previous human smuggling investigation, the Marine Corps said in a statement Thursday. At least eight other Marines have also been questioned about their involvement in alleged drug offenses.

None of the arrested or detained Marines were a part of the Southwest Border Support mission, according to the military’s statement.

Two Marines had been taken into custody July 3 for allegedly helping to smuggle undocumented immigrants across the southern border into San Diego County. The men allegedly received the migrants at a pickup point about 20 miles east of a U.S. port of entry at Tecate and seven miles north of the border, officials said earlier this month.

Tamara Lawrence, public affairs officer for Naval Special Warfare Command, said in a statement that “the loss of confidence outweighed potential operational risk.”

“Leaders at all levels must lead in a way that sustains and sharpens that foundation,” Lawrence said. “Discipline is a competitive advantage and enforcing those standards is critical to our success on the battlefield.”

The U.S. Marine Corps could not immediately be reached for further information.