Campbell told reporters in Seoul the United States is in talks with key players at the UN, including China and Russia, over potential sanctions against Pyongyang.

 

　　Last month, North Korea launched a satellite on the back of a long-range rocket in what Washington and its close allies suspect was a disguised missile test.

 

　　Pyongyang, banned by UN resolutions from conducting any ballistic missile tests, said the launch was for scientific and peaceful purposes only.

 

　　Campbell also said his visit to South Korea and Japan aims to calm tensions between the two U.S. allies.

 

　　"I think there is a very strong determination in South Korea to make sure that relations between South Korea and Japan are positive, going forward. We support that. We have great confidence in the leadership in both Japan and South Korea to recognise it as the strongest, best interests for both countries to maintain that positive trajectory going forward."

 

　　The Japan-South Korea dispute intensified in August when President Lee Myung-bak became the first South Korean leader to set foot on islands claimed by both countries.

 

　　The islands are known as Dokdo in Korea and Takeshima in Japan.

 

　　Campbell along with other US security officials are expected to leave South Korea later on Wednesday for Japan.