The two sides started the Ssangyong (Double Dragon) exercise last Sunday near Pohang, in the South Korean province of North Gyeongsang, in connection with the annual Foal Eagle field training between the two allies, the Yonhap agency said.
South Korea has said that the combined maneuvers ended as planned and that the US forces that joined the exercise will return to their bases, like Okinawa in Japan.
Among the US assets mobilized for that exercise were the USS Wasp, an amphibious multi-purpose assault ship of 40,500 tons, and the USS Bonhomme Richard, a ship of the same class.
The Wasp was carrying several F-35B stealth fighters, capable of taking off and landing vertically.
The exercise takes place annually but is carried out on a large scale every two years, involving more than 10,000 US Marines, mostly stationed in Okinawa, and thousands of South Korean marines.
The Ssangyong is intended to create and maintain fundamental military training throughout the alliance, according to the Combined Forces Command.