The release of American missionary Kenneth Bae and Matthew Todd by North Korea was widely welcomed while raising questions about why the reclusive State made the gesture.

North Korea freed two Americans on November 8 after it sentenced them to hard labor in separate and unrelated trials.

But mystery surrounded the release.

"Is it a sign Pyongyang wants better relations with Washington? Is it sending a message to its closest ally, China? Or is it a bid to shift the focus off its human rights record amid talk Kim could be charged with crimes against humanity?" CNN wrote.

"I think right now there is a charm offensive," Gordon Chang, the author of "Nuclear Showdown: North Korea Takes On the World," told CNN.

Something in Pyongyang, Chang believes, triggered the offensive. But what it was is uncertain.

Prior to the weekend's surprising development, Kenneth Bae and Matthew Todd Miller served hard labor for various crimes the government claimed they did while in North Korea.

The development came after U.S. President Barack Obama dispatched his National Intelligence director James Clapper to Pyongyang to serve as his personal envoy to North Korea.

Clapper carried a letter from Obama, which was purportedly brought to Kim Jong-Un.

In a statement, North Korea said it received an "earnest apology" from Obama for the actions of Bae and Miller.

Pyongyang observed them to be "sincerely repentant of their crimes and (were) behaving themselves while serving their terms," a CNN report said.

The chairman of North Korea's National Defense Commission - one of the several positions concurrently held by Kim -ordered the release of the captives.

Kim earlier demanded that Obama send a Cabinet member to discuss the release. This was an action one U.S. official described as a means of Pyongyang to project it had clout to continue solidifying the ruler's power.

Though Clapper is not a member of Obama's Cabinet, he is the U.S.'s spy chief.

Bae, a Christian missionary, had been convicted of attempting to bring down the government through religion. Aside from his missionary work, Bae ran a company that organized tours in the reclusive State.

In April 2013, a North Korean court sentenced Bae to 15 years of hard labor.

Authorities in Pyongyang accosted Miller in April this year and accused him of ripping apart his tourist visa and seeking asylum upon entering the country. A court sentenced him to six years of hard labor.

Bae and Miller are believed to be the last Americans taken captives by North Korea.

"I do believe it's a positive sign," Bill Richardson, a former U.S. ambassador to the United Nations who tried to win Bae's release during a 2013 visit to North Korea, told CNN.

With North Korea "catching a lot of grief" on its human rights record in the United Nations, Richardson said it appears Pyongyang is sending a message that "we're ready to talk."