South Korea ? The United States did not act to prevent a recent shipment of arms from North Korea to Ethiopia, even though sketchy intelligence indicated the delivery might violate a U.N. Security Council resolution restricting North Korean arms sales, Bush administration officials said Saturday.

The decision to let the shipment proceed was made by relatively low-level staffers, with little internal debate, and it was unknown to top policymakers involved in the campaign to punish Pyongyang for its test of a nuclear weapon last October, officials said.

The January arms delivery occurred as Ethiopia was fighting Islamic militias in Somalia, aiding U.S. policies of combating religious extremists in the Horn of Africa.

Intelligence reports indicated that the shipment included spare parts, including tank parts, officials said. Nevertheless, the cargo was not inspected, making it difficult to know whether it violated the U.N. resolution. The value of the shipment is also unclear.