U.S. Defense Secretary Robert Gates will arrive in Seoul Sunday for a six-day trip.

Gates is scheduled to co-chair with South Korean Defense Minister Kim Tae-young the 41st annual Security Consultative Meeting to open in Seoul for two days from Tuesday.

Both officials will discuss strengthening their bilateral military alliance, the planned transfer of wartime operational command to South Korea, and measures to North Korea's nuclear threat.

The visit will likely provide the opportunity for the U.S. to reaffirm its commitment to defend South Korea based on a pledge to strengthen the nuclear nonproliferation regime. The pledge was made at the June summit talks between President Lee Myung-bak and U.S President Barack Obama in Washington.

Gates will then go to Tokyo for talks with Japanese Prime Minister Yukio Hatoyama, Defense Minister Toshimi Kitazawa and Foreign Minister Katsuya Okada on key regional issues, including North Korea’s nuclear issue.