News reports from Seoul say South Korea's newly appointed nuclear negotiator will visit the United States ahead of next week's summit between the presidents of the two countries in Washington.

The reports Thursday come barely a day after Lim Sung-nam was appointed special envoy to six-nation talks on North Korea's nuclear disarmament. Lim's predecessor, Wi Sung-lac, was named ambassador to Russia.

Yonhap news agency says that during his three-day stay, Lim will meet with U.S. officials to coordinate a joint stance on North Korea's nuclear weapons programs, ahead of President Lee Myung-bak's summit with U.S. President Barack Obama October 13.

Quoting a foreign ministry statement, Yonhap says that Lim also will meet with officials at the U.S. State Department and the National Security Council to brief them on the results of last month's second round of inter-Korean denuclearization talks held in Beijing.

South Korea and the United States are discussing next steps toward reviving six-nation talks on North Korea's nuclear disarmament, which also include Russia, China and Japan.

Pyongyang abandoned those talks in 2009, but now wants to return to the negotiating table. South Korea and the United States are demanding proof that North Korean leaders are serious about aid-for-disarmament talks.