"We are beside ourselves," Lisa Ling said of the release. "We are beyond thrilled and so excited that we will finally be able to hold them in our arms." She called the long weeks since her sister's arrest in North Korea "the most unpredictable, challenging 4 1/2 months of our lives."
U.S. officials said that offering Bill Clinton as envoy was a high-stakes choice. The North Koreans, eager to have their importance acknowledged, were pleased at the idea of a visit from the former leader of the free world.
The plan was to give them, with the visit, "a gesture of respect - but that's all. No money, no flowery words," said a person familiar with the negotiations, who declined to be identified because of the sensitivity of the diplomacy.
He said that the administration also intends to continue trying to increase pressure on North Korea in response to recent nuclear tests and missile launchings that the United States and allies consider illegal.
U.S. officials have been trying to enlist other nations, especially in Asia, to clamp down on North Korea's nuclear and missile trade, and to try to cut it off from international financing to support that trade.
Clinton's mission risked domestic criticism that the administration was again rewarding one of the world's biggest weapons proliferators, a country that has repeatedly broken promises to the United States and its allies.
In Washington, reaction from conservatives was generally muted. Some congressional Republican aides said it was difficult to judge the mission until it was clearer what promises, if any, Clinton had made to Kim, and what the administration might give the North Koreans to try to resume the talks.
In Washington, White House spokesman Robert Gibbs denied Clinton went with a message from Obama. "That's not true," he told reporters.
"While this solely private mission to secure the release of two Americans is on the ground, we will have no comment" until the mission is complete, Gibbs said in a statement. "We do not want to jeopardize the success of former President Clinton's mission."
Clinton was accompanied by John Podesta, his one-time White House chief of staff, who also is an informal adviser to Obama.
Clinton was accorded honors typically reserved for heads of state. Senior officials, led by Vice Foreign Minister Kim Kye Gwan, who also serves as the regime's chief nuclear negotiator, met his private unmarked plane as it arrived Tuesday morning.
Video from a television news agency showed Clinton exchanging warm handshakes with officials and accepting a bouquet of flowers from a schoolgirl.
Kim later hosted a banquet for Clinton at the state guesthouse, Radio Pyongyang and the Korean Central Broadcasting Station reported. The VIPs and Kim posed for a group shot in front of the same garish mural depicting a stormy seaside landscape that Clinton's secretary of state, Madeleine Albright, posed in front of during her historic visit to Pyongyang in 2000.
But not long ago, North Korea's Foreign Ministry had harsh words for Clinton's wife, describing her as "a funny lady" who sometimes "looks like a primary schoolgirl and sometimes a pensioner going shopping."
The Associated Press contributed to this article.
