Talks between the two defense chiefs focused on how to ease the crisis over North Korea's nuclear weapons program but ministry officials declined to give details.

Ivanov, the third Russian defense chief to visit to Seoul since the normalization of diplomatic relations in 1990, is to meet with South Korean President Roh Moo-Hyun later in the day.

The Ivanov-Cho meeting followed Wednesday's UN Security Council meeting in which Russia and China blocked a common statement on North Korea's nuclear program.

The United States has sought to bring UN pressure to bear on Pyongyang, but China and Russia argued that such a move would push the Stalinist country deep into isolation.

Washington believes Pyongyang has one or two nuclear bombs and could make several more within six months if it continued on its present course.

While acknowledging that the Security Council was unable to issue a common statement on the crisis, US ambassador to the world body John Negroponte did not rule out UN action in the future.

Pyongyang wants direct talks with the United States and a non-aggression pact, but Washington has rejected the offer saying the crisis should be solved through multilateral channels.

SPACE.WIRE