Israel says it has intercepted a ship in the Red Sea carrying Syrian-made "advanced weaponry" being shipped from Iran to Palestinian fighters in Gaza.
The Israeli military said the weapons were shipped overland to Iran and then onward towards Gaza by sea.
Iran and Syria have long provided aid to both Lebanon's Shia movement, Hezbollah, and to armed Palestinian groups.
"During a complex covert navy operation in the early hours of this morning, the navy intercepted a cargo vessel in international waters between Sudan and Eritrea that was carrying an Iranian shipment of advanced weapons," Lieutenant Colonel Peter Lerner said.
"Dozens of surface-to-surface M302 Syrian-manufactured rockets were found," Lerner said, adding that the crew of the ship, named the Klos-C, had "fully co-operated".
The military said in an earlier statement it had "prevented an attempt to smuggle an Iranian shipment of advanced weaponry intended for terrorist organisations operating in the Gaza Strip".
Earlier on Wednesday, Israel claimed to have killed two fighters belonging to Hezbollah as they tried to plant a bomb near the Israeli-Syrian frontier.
That incident came a week after Israel reportedly bombarded positions of its arch-enemy Hezbollah inside Lebanon.