A U.S. MH-60 helicopter lands on South Korea's 14,500-ton amphibious landing ship Marado during a combined exercise held in waters off Okinawa, June 2, in this photo released by the Joint Chiefs of Staff. Yonhap

South Korea and the United States staged a combined exercise in international waters off Okinawa this week, the military said Saturday, in yet another move highlighting the allies' joint defense posture.

The three-day exercise, which ended Saturday, was aimed at bolstering the allies' mission capabilities against North Korea's provocations, according to the Joint Chiefs of Staff (JCS).

Korean vessels included the 14,500-ton amphibious landing ship Marado, the 7,600-ton destroyer, Sejong the Great and the 4,400-ton destroyer Munmu the Great. The ships were on their way to Hawaii to participate in a U.S.-led multinational maritime exercise set to begin in late June.

The U.S. Navy also mobilized the nuclear-powered aircraft carrier USS Ronald Reagan, the cruiser USS Antietam, the Aegis-equipped USS Benfold, and the replenishment tanker USNS Big Horn.