A U.N. panel of experts said in a confidential report that Iran violated a Security Council resolution on Oct. 10 when it tested a medium-range ballistic missile capable of delivering nuclear weapons.

U.S. officials said this month that Iran launched a second ballistic missile Nov. 21. The U.S. asked the U.N. Security Council on Tuesday to take action against Iran for that and the Oct. 10 violation, diplomats said.

The Security Council adjourned after about an hour of discussing the report without any resolution being introduced. Diplomats said the members likely would review the U.S. request, but that punitive measures were unlikely and did not have the support of Russia and China—two nations with veto power. […]