U.S. Senator John McCain will fly into Seoul Sunday to promote improved human rights conditions in North Korea, sources here said Wednesday.

The Arizona senator will stay until Monday while meeting with local activists, promoting the enhancement of human rights conditions in North Korea, the sources said. The U.S. embassy here refused to confirm the visit.

McCain, the Republican presidential nominee in 2008, has taken a hawkish stance on the communist North, which is viewed as a country having one of the worst human rights records.

McCain is also seeking the chance to meet with South Korean Foreign Minster Yun Byung-se, the sources said, adding that the main purpose of his visit is unknown.

He will be accompanied by fellow Senator Sheldon Whitehouse. It will be McCain's first South Korean trip since 1991.

U.S. Rep. Charles Rangel (D-NY), a Korean War veteran, will also come to Seoul Saturday at the invitation of the South Korean National Assembly, according to the sources.

The congressman will stay in South Korea for one week until Aug. 30 as part of an exchange program between the parliaments of the two countries.

"Rep. Rangel will be the first to be invited by the parliamentary exchange program under the Park Geun-hye government," a source said. "He was chosen as we've entered the 60th anniversary of the South Korea-U.S. alliance, and we have a number of Korean Americans in New York."

Rangel has been awarded by the South Korean government, the Korea Veterans Association and the Korean American Foundation for his contribution to enhancing Korea-U.S. ties. (Yonhap News)