Signs Stir Concern North Korea Might Test Nuclear Bomb Diplomat in Asia to Confer With Officials By Glenn Kessler Washington Post Staff Writer Saturday, April 23, 2005; Page A13 U.S. officials are increasingly concerned that North Korea may be preparing its first test of a nuclear weapon, though they warn that the information is sketchy and not definitive. A top U.S. diplomat, Assistant Secretary of State Christopher R. Hill, flew to the region yesterday to consult over the weekend with officials in Beijing, Tokyo and Seoul about the signs that a test may be in the works. Officials especially want...