A British Royal Navy vessel seized a sophisticated shipment of Iranian missiles in the Gulf of Oman earlier this year, officials claimed, presenting it as proof of Tehran’s support for Yemen’s Houthi rebels in the war-torn country. The British government’s statement was startling as it provided some of the strongest evidence yet that Tehran is arming the Houthis against the Saudi-led military coalition with advanced weapons smuggled through the Gulf. The UK embassy in the UAE described the seizure of surface-to-air missiles and engines for land-attack cruise missiles as “the first time a British warship has intercepted a vessel carrying such sophisticated weapons from Iran”. “The UK will continue to work to support a lasting peace in Yemen and is committed to international maritime security so that merchant shipping can transit safely without the threat of disruption,” said James Hippey, UK Defense Secretary . Iran’s mission to the United Nations did not respond to a request for comment. The announcement marks an escalation, as Western officials have previously shied away from public statements that definitively accuse Iran of arming Yemen’s Houthis with military contraband. However, the route of contraband through the Arabian Sea or the Gulf of Aden strongly suggests their destination. Despite a United Nations Security Council arms embargo on Yemen, Iran has long been suspected of supplying the Houthis with rifles, rockets, missiles and other weapons since the war in Yemen began in 2014. Iran denies arming the Houthis, but independent experts, Western nations and UN experts have traced evidence back to Iran. Citing a forensic analysis last month, the British navy linked the batch of rocket engines seized earlier this year to an Iranian-made cruise missile with a range of 1,000 kilometers (621 miles) that it said the rebels have used against Saudi Arabia. The Houthis also used the cruise missile to attack oil facilities in Abu Dhabi in January this year, the British navy said, an attack that killed three people and threatened the United States’ key ally’s reputation as a haven of stability. The US military fired interceptor missiles during the attack, signaling the widening of the war in Yemen. HMS Montrose’s helicopter was scanning for illicit goods in the Gulf of Oman on 28 January and 25 February when it spotted small vessels speeding away from Iranian shores with “suspicious cargo on deck”. A team of Royal Marines then stopped and searched the boats, seizing the weapons in international waters south of Iran. A US Navy guided-missile destroyer supported the British warship’s operation in February. Fifth Fleet Vice Admiral Brad Cooper said the seizure reflects the Navy’s “strong commitment to regional security and stability.” The Houthis seized Yemen’s capital, Sanaa, in September 2014 and forced the internationally recognized government into exile. A Saudi-led coalition armed with US weapons and intelligence joined the war on the side of the Yemeni government in March 2015. Years of fighting have led to a bloody stalemate and pushed the Arab world’s poorest nation to the brink of famine. A tenuous truce that began during the Muslim holy month of Ramadan in April appears to be holding, although both sides have accused each other of violations.