Seoul, Mar 21 (IANS): A visiting US nuclear envoy met South Korea's major presidential contenders here on Tuesday to discuss Pyongyang and other pending diplomatic issues, officials said.

Joseph Yun, the special representative for North Korea policy in the State Department, will be in Seoul until Thursday and hold talks with senior security officials including his counterpart Kim Hong-kyun, Yonhap News Agency reported.

Yun arrived in Seoul late Monday from Beijing where he met with Chinese officials to coordinate responses to North Korea's growing nuclear and missile threats.

Yun met with two centrist presidential hopefuls -- South Chungcheong province Governor An Hee-jung and former ruling party leader Yoo Seung-min, the officials said.

An, affiliated with the Democratic Party, ranked second in a poll conducted last week, with a 15.6 per cent approval rating. Yoo from the Bareun Party came seventh with 3.8 per cent.

An adviser to An told Yonhap News Agency that the meeting with Yun was arranged at Washington's request.

"The two sides discussed a wide range of diplomatic and security issues, including Terminal High Altitude Area Defence (Thaad) missile system, North Korea and China policy," he said, and added, "The meeting lasted more than one hour. It was productive and in a good mood."

South Korea will hold an early presidential election on May 9 following the Constitutional Court's ruling to oust Park Geun-hye on March 10 over a massive corruption scandal.