A massive joint South Korea-U.S. naval exercise kicked off in the East Sea on Sunday in response to North Korea's torpedo attack on the South Korean Navy corvette Cheonan in March.
A military spokesman said Korean and U.S. warships including the 97,000-ton nuclear-powered U.S. aircraft carrier George Washington left Busan Base for the East Sea to take part in the exercise en route while traveling north to waters north of Ulleung Island.
Code-named "Invincible Spirit," the four-day exercise will include anti-submarine, tactical maneuver, firing, air formation, and anti-marine commando training.
Meanwhile, North Korea in a statement Saturday reiterated threats of a "retaliatory sacred war" using its "nuclear deterrent" in response to the exercise. Such threats are frequent, but South Korean intelligence said they observed no unusual troop movements in the North.