North Korean state media reports that leader Kim Jong Il has pardoned two American journalists and ordered their release during a surprise visit by former U.S. President Bill Clinton. Word of the release came on a day when official Washington said little about Mr. Clinton's mission.

Bill Clinton traveled to North Korea to secure the release of American journalists Laura Ling and Euna Lee. The two women were arrested in March for illegally crossing the border from China into North Korea. They were working on a story about refugees for Current TV, which was co-founded by Mr. Clinton's former vice president, Al Gore.

Throughout the day Tuesday, U.S. officials said little about Mr. Clinton's mission, describing the effort as private and sensitive.

Presidential spokesman Robert Gibbs briefed reporters at the White House.

"I put out a statement that this was a private mission that we weren't going to comment on while the former president was on the ground in North Korea, and as a result of that I don't have anything more to add on this at this time," he said.

Reporters also pressed State Department spokesman Robert Wood to comment on the Clinton mission, but without success.

"I don't have anything I can add to it. The White House statement spoke for itself. At this point I don't have anything further on it, so you might want to save your questions," he said.

Mr. Clinton undertook his mission at a time of heightened tension between the United States and North Korea over its nuclear program. Pyongyang conducted a nuclear test in May and has also tested several ballistic missiles in recent months.

Since news of the Clinton mission to North Korea broke, there has been discussion among some experts and policy makers that the visit could set the stage for an improvement in U.S. relations with the government in Pyongyang.

Senator Lindsay Graham, a Republican from South Carolina, spoke about that on NBC's Today program.

"You would expect that you would not send a former president knowing that he is not likely to be successful. From the family point of view of the young ladies, this is great news and maybe we can build upon this to do something better when it comes to nuclear weapons," he said.

Many analysts believe that Mr. Clinton would not have gone to North Korea without a reasonable expectation for success.

Juan Zarate worked on the National Security Council during the George W. Bush administration and is now an expert on international threats at the Center for Strategic and International Studies in Washington.

"If President Clinton returns without having secured their release, it would be a major problem for the Obama administration and I think it would be a problem for the North Koreans too. I think it would show that they are not acting in good faith. For that reason, President Clinton is probably thinking that this is going to be a successful mission," said Zarate.

Mr. Clinton is the second former U.S. president to visit North Korea. Former President Jimmy Carter led a mission in 1994 that eventually led to a breakthrough accord on North Korea's nuclear program.