The US Navy's Fifth Fleet said on Saturday it had intercepted a fishing trawler smuggling "more than 50 tons of ammunition rounds, fuses and propellants for rockets" in the Gulf of Oman along a maritime route from Iran to Yemen on Dec. 1.

"Navy personnel operating from expeditionary sea base USS Lewis B. Puller (ESB 3) discovered the illicit cargo during a flag verification boarding, marking US 5th Fleet’s second major illegal weapons seizure within a month," it added in a statement.

"This significant interdiction clearly shows that Iran's unlawful transfer of lethal aid and destabilizing behavior continues," Vice Admiral Brad Cooper said.

"US naval forces remain focused on deterring and disrupting dangerous and irresponsible maritime activity in the region."

The fishing trawler intercepted on Thursday was carrying nearly 7,000 rocket fuses and "over 2,100 kilograms of propellant used to launch rocket propelled grenades", the statement said.

"The direct or indirect supply, sale or transfer of weapons to the Houthis in Yemen violates UN Security Council Resolution 2216 and international law," it added.

Last month the US navy said it had scuttled a boat transporting "explosive materials" from Iran to supply the Houthis, with enough power to fuel a dozen ballistic rockets.