S. Korea, U.S. start naval drills near N. Korean border

South Korea and the United States began on Sunday large-scale joint naval exercises in the Yellow Sea just days after North Korea's artillery attack on a South Korean island that killed four people, the Yonhap news agency said.

A U.S. naval task force led by nuclear-powered aircraft carrier the USS George Washington has joined several South Korean destroyers, frigates, support ships and anti-submarine aircraft for four days of military drills in waters about 125 km (77 miles) south of the border between the two Koreas.

"Participating units will conduct live-fire shooting and bombing drills," Yonhap quoted a South Korean military official as saying.

Washington and Seoul claim these are defensive drills aimed at deterring North Korea from launching further attacks across its disputed maritime border with South Korea, while Pyongyang has condemned the exercises as a provocation and threatened they could lead to a war.

North Korea opened artillery fire on the South's Yeonpyeong Island in the Yellow Sea Tuesday, killing two South Korean marines and two civilians. Sixteen others were injured, along with three civilians. The South retaliated and warned of further strikes. The North later accused South Korea of attacking first.

Western powers condemned the attack and warned against a further escalation. Russia called on both Koreas to refrain from the use of force.

North and South Korea remain technically at war, since no peace treaty was signed following the Korean War in 1953. The Demilitarized Zone between the countries is the most heavily armed border in the world.