WASHINGTON -- The Bush administration has given up its push for an international ban on sales of uranium-enrichment technology to nonnuclear states, a move that will complicate its nuclear diplomacy toward both Iran and India, and could open the way for a wave of new entrants into the enrichment club.

The concession was made under heavy pressure from Canada, which wants the right to build uranium-enrichment plants to export the lucrative enriched fuel for nuclear-power plants. It marks an about-face for President Bush, who...