The U.S. Navy has seized an arms shipment of thousands of illicit assault weapons, machines guns and sniper rifles hidden aboard a ship in the Arabian Sea likely headed for Yemen, officials have said. The U.S. fifth fleet, based in Bahrain, announced on Sunday that the guided-missile cruiser USS Monterey discovered the weapons aboard a stateless dhow – a traditional Mideast sailing ship – in an operation that began Thursday in the northern reaches of the Arabian Sea off Oman and Pakistan. An American defense official said the weapons resembled previous shipments which have been intercepted that were bound for Houthi rebels in Yemen. The Navy’s initial investigation found the vessel came from Iran, AP reported. Iran’s mission to the U.N. did not immediately respond to AP’s request for comment on the seizure but Tehran has denied providing rebels with weapons in the past. The Navy seized nearly 3,000 Chinese Type 56 assault rifles, a variant of the Kalashnikov. They also recovered hundreds of other heavy machine guns and sniper rifles, as well as dozens of advanced, Russian-made anti-tank guided missiles. The shipments also included several hundred rocket-propelled grenade launchers and optical sights for weapons, AP reported. Sailors boarded the vessel and found the weapons, most wrapped in green plastic, below deck.