Early Wednesday morning, a special operations unit of the Israeli navy conducted what appears to be a long-planned boarding operation of a Panamanian-flagged ship, the Klos-C, which was transiting the Red Sea en route to Port Sudan. Members of the Shayetet 13 commando unit (Israel’s version of the U.S. Navy’s SEAL teams) seized “numerous advanced weapons” believed to be destined for Gaza, which is controlled by Hamas.

According to the IDF, concealed among the Klos-C’s commercial cargo were dozens of large artillery rockets identified as “M-302 surface-to-surface missiles.” Based on the rockets’ origin in Syria and description, the M-302 appears to be a derivative of the 302mm “Khaibar” rocket, which Hezbollah fired at Israel during the 2006 war.

By modern military standards, the Khaibar is a fairly crude weapon that is similar to the larger variants of the homemade Qassam rocket, which Hamas already possesses. Like Qassam rockets, the Khaibar is unguided and extremely inaccurate. However, the Khaibar’s 62 mile range (100 km) and 385 pound (175 kg) warhead make it more lethal than the Qassam.

Similar in design to the Chinese WS-1 rocket, the Khaibar is not practical for Western armies. Its inaccuracy necessitates firing multiple rockets to have a realistic chance of hitting the target — a task more easily accomplished by precision aerial bombing. But if the goal is to terrorize an adversary, the Khaibar is the ideal terror weapon.

In the 2006 war in Lebanon, Hezbollah fired the Khaibar repeatedly into Israel, hitting Haifa, Afula, and as far south as the town of Hadera. From Gaza, the Khaibar would easily be able to reach Tel Aviv, Jerusalem, and several important Israeli installations in the Negev desert, including the air bases at Ramon and Hatzerim, as well as the Negev Nuclear Research Center.

It is unclear whether the Khaibar shipment was destined for Palestinian Islamic Jihad, Hamas, or other violent groups in the Gaza. Regardless, yesterday’s seizure demonstrates Syria and Iran’s persistent attempts to better equip their proxies in Gaza, and Sudan’s continued complicity in that effort.

Patrick Megahan analyzes military hardware for militaryedge.org, a project of Foundation for Defense of Democracies.