The U.S. Navy said Tuesday it intercepted a shipment of assault rifles last week bound for Yemen that it believes came from Iran. 

A statement from the U.S. 5th Fleet said 2,116 AK-47 assault rifles were found on a fishing vessel in the Gulf of Oman that was traversing “a route historically used to traffic illicit cargo” to Yemen’s Iran-backed Houthi rebels. 

The statement said U.S. forces had intercepted two other fishing vessels in the same area during the past two months that were also carrying weapons from Iran to Yemen. 

“This shipment is part of a continued pattern of destabilizing activity from Iran,” said Vice Adm. Brad Cooper, commander of U.S. Naval Forces Central Command, U.S. 5th Fleet and Combined Maritime Forces. “These threats have our attention. We remain vigilant in detecting any maritime activity that impedes freedom of navigation or compromises regional security.” 

Iran has repeatedly denied arming the Houthis, while independent and U.N. experts have traced components from seized shipments back to Iran. 

Yemen erupted into conflict in late 2014 when the Houthis seized the capital.  The fight escalated in early 2015 with the entry of a Saudi-led coalition fighting on the side of Yemen’s exiled government. 

A six-month cease-fire expired in October, and the years of fighting has left millions in Yemen in need of humanitarian aid. 

Some information for this report came from The Associated Press.