The conclusion of the council's Panel of Experts on Iran will likely lead to calls for expanding sanctions against Tehran in Washington and some other Western capitals. The White House said on Tuesday that it would not rule out additional steps against Tehran over the missile test.
"On the basis of its analysis and findings the Panel concludes that Emad launch is a violation by Iran of paragraph 9 of Security Council resolution 1929," the panel said in its report.
Reuters on Tuesday reviewed the 10-page report, which was dated Dec. 11 and went to members of the United Nations Security Council's Iran sanctions committee in recent days. The report is expected to come up later on Tuesday when the 15-nation council discusses the Iran sanctions regime.
The report said the panel considers ballistic missiles capable of delivering nuclear weapons to be those that can deliver at least a 500 kg payload within a range of at least 300 km.
"The Panel assesses that the launch of the Emad has a range of not less than 1,000 km with a payload of at least 1,000 kg and that Emad was also a launch 'using ballistic missile technology'," the report said.
The launch took place on Oct. 10, according to the report. The panel noted that Iranian rocket launches from 2012 and 2013 also violated the U.N. ban on ballistic missile tests.
The U.N. report could put President Barack Obama's administration in an awkward position, since Iran has said that any new sanctions would jeopardize a July 14 nuclear deal between Tehran and six world powers. But if Washington failed to call for sanctions it would likely be perceived as weakness.
Diplomats say it is possible for the UN sanctions committee to blacklist additional Iranian individuals or entities, something Washington and the Europeans are likely to ask for. However, they said Russia and China, which dislike the sanctions on Iran's missile program, might block any such moves.
Republicans in Congress who disapprove of the Iran nuclear deal are likely to seize on the UN panel's findings as grounds for additional congressional US sanctions.
While ballistic missile tests may violate UN Security Council sanctions, council diplomats note that such launches are not a violation of the nuclear deal, which is focused on specific nuclear activities by Iran.
Asked about the panel's report, British UN Ambassador Matthew Rycroft told reporters it was "absolutely crucial that the Security Council upholds its responsibilities and does respond effectively to what appears to have been a breach."
The expert panel did not mention a second reported missile test that Iran carried out last month. The panel produced its report after the United States, Britain, France and Germany in October called on the UN sanctions committee to take action in response to Iran's test of an Emad missile.
Iran's UN mission did not respond immediately to a request for comment. In October Tehran disputed the Western assessment that the missile was capable of delivering a nuclear warhead.
"None of the Islamic Republic of Iran's missiles has been designed for a nuclear capability," Iranian Foreign Minister Mohammad Javad Zarif said at the time.
Security Council resolution 1929, which bans ballistic missile tests, was adopted in 2010 and remains valid until the nuclear deal is implemented.
Under that deal, most sanctions on Iran will be lifted in exchange for curbs on its nuclear program. According to a July 20 resolution endorsing the deal, Iran is still "called upon" to refrain from work on ballistic missiles designed to deliver nuclear weapons for up to eight years.
The experts' report noted that ballistic missile launches would still be covered by the July 20 resolution.
Earlier on Tuesday the UN nuclear watchdog's 35-nation board in Vienna closed its investigation into whether Iran sought atomic weapons, opting to back the international deal with Tehran rather than dwell on Iran's past activities, diplomats said.
US Secretary of State John Kerry issued a statement welcoming the decision to close the investigation into whether Iran once had a secret nuclear weapons program.
