Yemen's Houthi rebels are still arming themselves with ballistic missiles and drones that "show characteristics similar" to Iranian-made weapons, a report by a United Nations panel of experts found.
The panel said it "continues to believe" that short-range ballistic missiles and other weaponry were transferred from Iran to Yemen after an arms embargo was imposed in 2015.
Iran has repeatedly denied it is arming the Houthis in Yemen, but the United States and Saudi Arabia have accused Tehran of providing military support.
Recent inspections of weaponry including missiles and unmanned aerial vehicles (UAVs) used by the Houthis "show characteristics similar to weapons systems known to be produced in the Islamic Republic of Iran", said the 125-page report.
During recent visits to Saudi Arabia, the panel was able to inspect debris from 10 missiles and found markings that suggest an Iranian origin, the report stated. The study spans January to July.
"It seems that despite the targeted arms embargo, the Houthis continue to have access to ballistic missiles and UAVs to continue and possibly intensify their campaign against targets in KSA [Saudi Arabia]," said the experts.
The panel said there was a "high probability" that the missiles were manufactured outside of Yemen, shipped in sections to the country and reassembled by the Houthis.
In a letter to the panel, Iran maintained that the missiles, which the Houthis call the Burkan, are a domestic upgrade of Scud missiles that were part of Yemen's arsenal before the start of the war.
The experts are also investigating information that the Houthis received monthly shipments of fuel from Iran valued at $30 million (Dh110m). Iran has denied providing any financial support.
During the inspections of the missile debris, they also found power converters produced by a Japanese company and Cyrillic markings on components that suggested a Russian link. The investigation continues.
UN Secretary-General Antonio Guterres said in June that some components from five missiles fired at Saudi Arabia were manufactured in Iran but that UN officials were unable to determine when they were shipped to Yemen.
The Houthis are accused of widespread and indiscriminate use of landmines.
Since 2015, Saudi Arabia has been leading a military campaign to push back the Houthis and restore the internationally recognised government to power.
The UN considers the conflict, which has left nearly 10,000 people dead in Yemen, to be the world's worst humanitarian crisis.
Houthis claim they will halt Red Sea attacks for two weeks
Three injured in car bomb explosion in Aden, Yemen
Strait of Hormuz is not the most dangerous risk for blockade
Omani foreign minister meets Pompeo to discuss Yemen
The report was released hours before Houthi rebels said they were willing to unilaterally halt attacks on Red Sea shipping in order to allow peace talks to move forward, after weeks of obstructing UN-led efforts.
The announcement comes just a week after Saudi Arabia stopped oil tanker routes through the narrow Bab El Mandeb Strait – one of the world’s most important shipping lanes – after Houthi rebels fired missiles at commercial vessels. Other Gulf states mulled similar moves.
"The unilateral halt in naval military operations will be for a limited time period and could be extended and include all fronts if this move is reciprocated by the leadership of the coalition," the head of the Houthi supreme revolutionary committee, Mohammed Ali al-Houthi, said in a statement. But there was no indication when this would start or how long it would last.
There was no immediate comment from coalition forces but officials have accused the rebels of co-opting UN mediation to further their military objectives.
Last week, Yemeni foreign minister Khaled Al Yemany told The National that the Houthi are stalling UN peace negotiations in a bid to further entrench themselves in Hodeidah and drag the coalition into urban warfare in Yemen's biggest port city, the country's Foreign Minister said on Tuesday.
He warned that UN envoy Martin Griffiths should be aware they were “buying time” and that the halted offensive – paused to allow diplomatic efforts – could not be paused indefinitely.
The Arab-led coalition has called for the complete withdrawal of Houthi forces from the Red Sea port city of Hodeidah. The rebels have offered to hand the operation of the port facility - a vital lifeline for coalition and international aid to reach millions living under the Iran-backed group - to the UN but under their supervision.
This has been rejected by coalition and Yemeni government officials who say the full withdrawal is a prerequisite for ceasefire and peace talks.
Gulf nations have warned of the threat of Houthi rebels to international trade as well as to regional security.