It inferred on Yahoo whilst both of them want the 6 party talks to resume that there are differences in approach/opinion maybe his expression has something to do with that.
Transcript of the speech which I have scanned but not read in depth maybe this gives further insight if one reads between the lines
http://www.whitehouse.gov/news/releases/2005/06/20050610-6.html
Thanks snugs and great job with the thread