U.S., S. Korea Set To Begin War Exercises Off Korean Peninsula

(CNN)

South Korea and the United States began assembling ships for joint war exercises Sunday off the west coast of the Korean peninsula in the Yellow Sea, a source at the South Korean Joint Chiefs told CNN.

The exercises are set to begin as diplomats worked to ease tensions in the Koreas after North Korea warned of unpredictable "consequences" if the United States fulfills its vow of deploying an aircraft carrier to the Yellow Sea for joint military maneuvers with South Korea.

The exercises are scheduled to begin at 3 p.m. Sunday (1 a.m. ET).

China's foreign minister spoke with his Russian, U.S., and Japanese counterparts, and a Chinese representative visited Seoul as envoys underscored the need to lower the temperature in the longtime flash-point region, days after four South Koreans died when North Korea shelled Yeonpyeong Island.

North Korea said the South provoked the Tuesday attack because shells from a South Korean military drill landed in the North's waters. South Korea was holding its annual Hoguk military drill when the North started its shelling, and the South returned fire.