Iran flew Islamic Revolutionary Guard Corps (IRGC) commanders, military advisers and missile- and drone-related equipment into Yemen this month, according to four sources, in a move that suggests Tehran is seeking to strengthen the ability of its Houthi allies to threaten Red Sea shipping.

Four sources familiar with the matter, including two Iranian sources, Yemen’s information minister and a regional security analyst, said Iran transferred the IRGC personnel and military-related equipment on a flight from Tehran to Yemen on July 13, a development that has not been previously reported.

The two Iranian sources said that between 10 and 21 IRGC personnel, including senior commanders, were on the Mahan Air flight.