Yemeni forces intercepted a ship on January 23 carrying a large cache of weapons - including surface-to-air missiles - that U.S. officials suspect were being smuggled from Iran and destined for Yemeni insurgents, officials said, Reuters reported.
Yemen's government said the arms intercepted aboard the ship off the country's coast also included military grade explosives, rocket-propelled grenades and bomb-making equipment, according to a statement by its embassy in Washington.
A U.S. official, speaking on condition of anonymity, confirmed the operation was coordinated with the U.S. Navy and that a Navy destroyer was nearby.
A second official told Reuters the intercepted shipment was believed to have been from Iran and destined for insurgents, likely Houthis.
"This demonstrates the ever pernicious Iranian meddling in other countries in the region," said the second U.S. official, who also spoke on condition of anonymity.
Iran denies any interference in Yemen's affairs.
Analysts and diplomats believe that the ascent of the Houthis, named after their leaders' family, has turned Yemen into a new front in a long struggle between Iran and Western powers and the Arab regimes they support.
Gulf Arab governments and Sunni clerical allies accuse Iran of backing Shi'ite communities around the region, and Sanaa has also accused Iran of trying to meddle in Yemeni affairs.
Yemen's President Abd-Rabbu Mansour Hadi snubbed a visiting Iranian envoy last year to signal "displeasure" with Tehran after Sanaa said it had uncovered an Iranian-led spy ring in the capital.
Earlier this month, the U.S. envoy to Yemen, Gerald Feierstein, was quoted accusing Iran of working with southern secessionists. Yemen is also grappling with al Qaeda militants in the north.
Its location flanking top oil producer Saudi Arabia - Iran's Sunni Muslim regional adversary - and major shipping lanes have made restoring its stability an international priority.
Yemen's government said in a statement the shipment was intercepted in Yemeni waters, close to the Arabian Sea. It said Yemeni Coast Guard officials boarded the vessel, which flew multiple flags and had eight Yemeni crew members on board.
"Authorities are continuing to investigate the vessel's shipping route by analyzing navigation records found on board the ship," the statement said.