San Diego, United States - February 26, 2025 San Ysidro, California - U.S. Marines are taking action at the southern border. From February 7-17, 2025, troops with the 1st Combat Engineer Battalion, 1st Marine Division, worked hard. They mounted concertina wire along the border wall near this busy crossing point. The goal is clear. They aim to boost security and stop illegal crossings. U.S. Northern Command has teamed up with the Department of Homeland Security for this effort. Physical barriers are key to their plan. The mission got a high-profile visit. On February 24, 2025, Sgt. Maj. Carlos A. Ruiz arrived. He’s the sergeant major of the Marine Corps. Ruiz spoke with Marines from I Marine Expeditionary Force at the same site. The barbed wire stretched across the wall behind them. The message was strong. Security here matters. The collaboration between military and homeland officials continues to tighten the border.