(CNN) -- With Americans Kenneth Bae and Matthew Todd Miller back in the United States, the big question now is why did North Korean leader Kim Jong Un agree to their 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? "I think right now there is a charm offensive," Gordon Chang, the author of "Nuclear Showdown: North Korea Takes On the World," told CNN.North Korea's ''charm offensive'' coincides with release of U.N. reportNorth Korea has released Kenneth Bae and Matthew T. MillerThere are questions about why Pyongyang freed the AmericansNorth Korea analysts and experts are divided over why it took the step
The official said there were no discussions about _'s nuclear program, and other U.S. officials told CNN there was no "quid pro quo" for the men's release.