American warships have intercepted five shipments of weaponry to the Houthis in Yemen from Iran in the past year and a half, according to US Vice Admiral Kevin Donegan, who is in charge of American naval operations in the Middle East.
The first intercepted shipment was in April 2015 and since then, American ships have intercepted an additional four shipments, Donegan says.
The shipments included thousands of AK-47 automatic rifles, as well as anti-tank missiles and sniper rifles.
The US Navy determined that the ships carrying the weapons came from Iran based on an examination of the GPS data on board the five vessels as well as from interrogations of their crews.
The crews of the vessels smuggling the weapons are typically unemployed fishermen hired just for the trip, according to Donegan.
Saudi Arabia, which launched a war last year in neighboring Yemen against the Houthis, has long claimed that the Houthis, who are Shia, are supported by Iran.
The discovery of these shipments gives credibility to those claims.