North Korea has warned that it will reconsider its moratorium on missile tests if the Bush administration doesn't resume contacts aimed at normalizing relations, a U.S. researcher who visited the North said Wednesday.

Officials also said North Korea will restart its nuclear program unless Washington makes progress on supplying two reactors promised in a 1994 agreement, said Selig S. Harrison, a senior fellow of the Century Foundation in Washington.

Harrison said the North's leaders are eager for ties with Washington but dismayed at President Bush's review of policy toward them and view recent U.S. gestures as confrontational.