In a letter to the 15-member council, Jonathan Cohen, the acting US Ambassador to the UN, said that Iran had tested a medium-range ballistic missile on December 1, 2018, and attempted to launch two satellites in orbit on January 15 and February 5.
Cohen wrote: “Iran has carried out these three launches in defiance of the expressed will of the UN Security Council, and such provocations continue to destabilize the entire Middle East region.”

He added: “The prospect of rapid escalation in the region is real, and increasingly likely, if we fail to restore deterrence.”

He called upon the council to “join [the US] in imposing real consequences on Iran for its flagrant defiance of the council’s demands and bring back tougher international restrictions to deter Iran’s missile programme”.

The UN resolution being referred to here is Security Council Resolution 2231, which enshrines the 2015 Iranian nuclear deal reached by Iran, Britain, France, Germany, China, Russia and the United States. It calls on Iran to refrain from work on ballistic missiles designed to deliver nuclear weapons until 2023.

Iran has argued that the wording makes this condition optional and Alireza Miryousefi, spokesman for the Iranian mission to the United Nations, claimed that its missiles are not designed to carry nuclear payloads so the resolution does not apply to these launches.

However, Iran has admitted to violating the nuclear accord, which the US pulled out of last May, by only pretending to shut down the reactor core, so why would we trust them now?
This is not the first time that the US has warned the UN about Iran’s missile programme.

In December, US Secretary of State Mike Pompeo urged the UNSC to toughed the resolution so that it left no room for interpretation, in the same way that a 2010 resolution did. He said it should ban Iran from “activity related to ballistic missiles capable of delivering nuclear weapons, including launches using ballistic missile technology”.

However, the US has not yet proposed as concrete action in the UNSC to toughen missile restrictions on Iran because such a move would likely be vetoed by Russia and China.
Most UN sanctions on Iran were lifted following the signing of the 2015 nuclear deal, but Iran is still subject to a UN arms embargo, among other things.

Europe has been scrambling to salvage the nuclear deal since the US pulled out.