Camp Pendleton, Calif. ? Brig. Gen. Rex McMillian watched proudly Friday from a scrubby bluff as hundreds of Marines in seafaring tanks hit the Southern California beach in perfect unison with support helicopters buzzing overhead.

An amphibious assault vehicle delivers U.S. Marines to the beach during operation “Dawn Blitz” Friday at Camp Pendleton, Calif.

It had been nearly 10 years since his Marines last trained in such a large-scale beach invasion exercise with the Navy.

With the wars in Afghanistan and Iraq taking troops to landlocked regions, many of the Marines had never been on a ship — let alone stormed a beach — until the “Dawn Blitz” exercise, the largest of its kind on the West Coast since the Sept. 11 terror attacks. The two-week training drill ended with 5,000 Marines and sailors staging the mock invasion.

The exercise came two days before the D-Day anniversary and at a pivotal time for the Marines as they face questions from Defense Secretary Robert Gates about whether major amphibious landings that made the Corps so famous worldwide are becoming outdated in today’s warfare.

As the sun streamed through dissipating morning clouds, the troops landed at exactly 9:15 a.m. as planned — 45 minutes after leaving the cavernous interior of the USS Bonhomme Richard about 20 miles off the coast of Camp Pendleton.

Seconds after rolling in with the deep-blue waves, the Marines poured from their tanks and took their positions, keeping low and aiming their assault rifles toward their imaginary enemy.

California’s morning freeway traffic flowed by on the horizon, with drivers unaware of the drill that Marines said was crucial to maintaining their skills as a versatile force for combat missions and humanitarian operations.

“I think they executed this superbly,” McMillian said, smiling.