WASHINGTON - Iran unveiled a new underground depot for its medium- range ballistic missiles on Tuesday, less than two months after testing one of the weapons considered illegal under international law.The missile, named the Emad, is capable of delivering a nuclear payload and is uniquely designed for that task. Their construction violates a 2010 United Nations Security Council resolution, according to the US State Department.An October 10 of the device prompted ire from the United States, which threatened new measures against Tehran in response. But Treasury Department plans last week to roll out new missile-related sanctions were scrapped last minute by the Obama administration, which is preparing to implement its landmark nuclear deal reached with Iran within the next several weeks.Revelation of the new silo – broadcast proudly on Iranian state television – is likely to agitate the administration further and provide fuel to its critics, who fear the nuclear deal holds the US captive to Iran as it pursues of other illicit activities, in the fields of human rights, terrorism and missile technology, with fewer constraints.The nuclear deal, formally known as the Joint Comprehensive Plan of Action, extends the ban on Iran’s ballistic missile activity for eight years. The ban then expires. Iran says its missile program has no relation to its nuclear program, which it has long maintained as exclusively peaceful.Iran’s president, Hassan Rouhani, ordered his defense minister last week to begin expanding the program. The country’s current missile program focuses on improving the precision, range and payload opportunities of the weapons.The Revolutionary Guards’ second- in-command, Brigadier General Hossein Salami, said last Friday that Iran’s depots and underground facilities are so full that they do not know how to store their new missiles.Reuters contributed to this report.