Will defend South Korea in emergency, assures US

The United States has vowed to use all available defence capabilities in emergency situations on the Korean peninsula to defend South Korea, the media reported on Monday.

The pledge was made by the US during an annual discussion between Seoul and Washington held at Vandenberg Air Force Base in California, Yonhap news agency cited Seoul's defence ministry as saying.

The discussion took place amid rising tensions on the peninsula after North Korea's fourth nuclear test on January 6 and the subsequent long-range rocket launch on February 7 using ballistic missile technology.

The US allowed South Korean military officials to observe its test launch of an unarmed Minuteman-3 nuclear missile that was conducted on Thursday in California.

The US officials also explained about the deployment process of B-52 long-range bombers on the Korean peninsula in emergency situations.

One B-52 bomber flew over South Korea's airspace on January 10, days after what North Korea claimed to be its first H-bomb test.

The US military reportedly plans to mobilise a nuclear-capable aircraft carrier and other strategic assets.

Combined forces of South Korea and the US are scheduled to kick off their annual war games in South Korea in March, which the North Korea has denounced as a rehearsal for northward invasion.