Three European powers have warned the UN that Iran is developing nuclear-capable ballistic missiles in violation of a Security Council resolution.
A letter sent by the UK, France and Germany says Iran tested a Shahab-3 missile variant "equipped with a manoeuvrable re-entry vehicle" that could deliver a nuclear weapon.
Such activity is "inconsistent" with a resolution endorsing the 2015 Iran nuclear deal, it argues.
Iran has denied the allegation.
Foreign Minister Mohammad Javad Zarif said the letter was a "desperate falsehood" put out by the European powers "to cover up their miserable incompetence in fulfilling bare minimum" of their obligations under the nuclear deal.
Latest E3 letter to UNSG on missiles is a desperate falsehood to cover up their miserable incompetence in fulfilling bare minimum of their own #JCPOA obligations— Javad Zarif (@JZarif) December 5, 2019
If E3 want a modicum of global credibility, they can begin by exerting sovereignty rather than bowing to US bullying. pic.twitter.com/QtfZFnLpO5
Security Council Resolution 2231 "calls upon" Iran not to "undertake any activity related to ballistic missiles designed to be capable of delivering nuclear weapons, including launches using such ballistic missile technology".
Iran has insisted that its nuclear programme is entirely peaceful and denied that its ballistic missile programme violates the resolution.
But the European letter says that video footage of a test posted on social media on 22 April showed the use of a Shahab-3 booster that was "a Missile Technology Control Regime Category-1 system", according to the Associated Press.
As such, it was "technically capable of delivering a nuclear weapon".
The Missile Technology Control Regime, which was established to address nuclear proliferation, says Category 1 systems are capable of delivering a payload weighing at least 500kg (1102lbs) a distance of at least 300km (186 miles).
AP said the letter also listed three other examples of Iranian activities that the UK, France and Germany considered to be "inconsistent" with resolution 2231:
Israel's Foreign Minister Israel Katz welcomed the letter, and instructed Israeli diplomats to present a "complete list of Iranian violations of the nuclear agreement" at a Security Council meeting on 19 December that is expected to discuss Iran.
France, Germany & the UK to the UN Sec-General: Iran is developing nuclear-capable missiles in breach of the nuclear agreement. The next step must be an effective military threat of a Western-Arab coalition led by the US to deter Iranian aggression. These are critical moments.— ישראל כ”ץ Israel Katz (@Israel_katz) December 5, 2019
Iran has breached a number of commitments under the deal in recent months in response to US President Donald Trump's decision last year to abandon the deal and reinstate economic sanctions.
Mr Trump wants to force Iran to negotiate a new agreement that would place indefinite curbs on its nuclear programme and also halt its development of ballistic missiles. Iran has refused to negotiate unless the US first lifts its sanctions.
The five other parties to the deal - the UK, France, Germany, China and Russia - have tried to keep it alive. But the sanctions have caused Iran's oil exports to collapse, the value of its currency to plummet and the inflation rate to soar.
In a separate development, US officials said a US Navy warship deployed in the Gulf of Oman had seized advanced missile parts believed to be headed from Iran to Yemen. The parts were on board a small boat stopped last week, they said.
The US defence department also denied a report in the Wall Street Journal that it was considering sending dozens more warships, other military hardware, and as many as 14,000 additional troops to the Middle East to counter Iran.