South Korea's top nuclear envoy left Sunday for the United States to fine-tune a strategy on North Korea.

Hwang Joon-kook, special representative for peace and security affairs on the Korean Peninsula, cited a change in security conditions on the peninsula due to a recent inter-Korean deal and some "positive results" in the latest South Korea-China summit talks.

The two Koreas struck a rare deal on Aug. 25 on ending a sharp military crisis, paving the way for additional dialogue.

The following week, President Park Geun-hye agreed with her Chinese counterpart, Xi Jinping, to continue efforts for the early resumption of the six-party nuclear talks aimed at denuclearizing North Korea. They were united in warning Pyongyang not to take provocative acts that raise tensions.

Just before the U.S. trip, Hwang said, it is to "hold in-depth discussions on how to deal with the North Korean nuclear and other issues in the latter half (of the year)."

He is scheduled to meet with Sung Kim, the U.S. special representative for North Korea policy, on Wednesday at the State Department in Washington. The North Korea issue is expected to be high on the agenda in the meetings.

Hwang will visit New York first for meetings with ambassadors there from the 15 U.N. Security Council members before heading to the U.S. capital.

"I will request active cooperation in general on issues of the council's concern, including the North Korean nuclear and missile issues," Hwang said.

South Korean officials say the North may test-fire a long-range rocket on the occasion of its founding anniversary of the communist party in October.

In the latter half of the year, the U.S. and China will hold a summit in late September and President Park will visit the U.S. in mid-October. (Yonhap)