The US and South Korean militaries have shown a part of large-scale amphibious landing drills to the media.
The forces of the two countries are carrying out the Ssang Yong “twin dragons” exercise with an eye on North Korea from August 26 through September 7.
Naval vessels and more than 40 military aircraft, including US F-35B stealth fighter jets are taking part.
On Monday, a drill in the southeastern city of Pohang was shown to the media. F-35B and other aircraft flew over the area, assuming an attack on an enemy base.
When amphibious vehicles landed on the beach one after another, armed soldiers got out and secured a base. Above in the sky, troops also practiced parachuting from transport aircraft.
The South Korean military says the US and South Korean commanders, who had been stationed on their respective ships, were on board together on a South Korean vessel for the first time in the joint exercise. It says the aim is to improve command and control.
The US and South Korean militaries have just carried out a regular joint military exercise aimed at addressing possible emergencies on the Korean Peninsula. It ended last Thursday.
The two countries are stepping up vigilance against ballistic missile launches and other activities by North Korea as the North has lashed out at such drills.