US Defence Secretary Robert Gates has said he and Secretary of State Hillary Clinton will visit the Demilitarised Zone dividing North and South Korea.

美国国防部长罗伯特·盖茨称，他将与国务卿希拉里·克林顿视察朝韩非军事区。

Mr Gates said their tour on Wednesday would serve "to highlight how important operations are there to the security of the peninsula（半岛） as well as the region".

The US secretaries of state and defence have never visited the DMZ together.

The joint¹ trip is also intended to show support for Seoul amid a row with Pyongyang over a warship's sinking.

The Cheonan, a South Korean navy corvette（轻巡洋舰） , went down on 26 March near the disputed maritime² border. Forty-six sailors were killed.

International investigators³ found a North Korean torpedo⁴（鱼雷，水雷） had sunk the ship, but Pyongyang rejects this and says it wants its own investigation⁵.

The UN Security Council has condemned⁶ the attack without assigning blame.

North and South Korea technically⁷ remain at war because their three-year conflict ended in an armistice⁸（停战，休战） in 1953 and no peace treaty was signed. The US has since stationed thousands of troops in South Korea.

'Steadfast⁹ commitment'

Speaking during a visit to Camp Casey, a US base 20 miles south of the Demilitarised Zone, Mr Gates said he and Mrs Clinton planned to meet US and South Korean troops deployed¹⁰ along the heavily-fortified frontier.

"Secretary Clinton and I, along with our Korean counterparts, will visit the DMZ to highlight how important operations are there to the security of the peninsula as well as the region and demonstrate our steadfast（坚定的，不变的） commitment to the [Republic of Korea]," he told reporters.

They will then attend high-profile security talks, where they will finalise plans for joint military exercises, including naval¹¹ manoeuvres（调动，演习） in the Yellow Sea and Sea of Japan (East Sea), intended to send a "clear message of deterrence¹²（威慑，妨碍物） ".

The nuclear-powered aircraft carrier, the USS George Washington, is due to arrive in the South Korean port of Pusan on Wednesday. Three other US destroyers are due in South Korean ports on the same day.

China has expressed concern over the naval exercises, but US officials say the drills will take place in international waters.

Mr Gates said the Security Council statement on the sinking of the Cheonan had been "pretty clear and pretty firm" in its condemnation¹³（谴责，非难） , and that the North's missile and nuclear proliferation（核扩散） posed a challenge.