Threats posed to Israel’s offshore gas rigs by the Lebanese terror group Hezbollah’s missile arsenal have prompted the Israeli Navy to add extra missile defense systems to its warships.

Four Israeli Navy Sa’ar 6 missile ships, which are currently being manufactured in Germany, will now be equipped with dual Iron Dome missile defense systems—as opposed to featuring a singular Iron Dome battery, the original plan for each ship.

A senior Israeli naval officer explained the upgrade to the ships’ defense systems stems from the threat posed by Hezbollah’s large weapons cache of medium- and long-range missiles, including Iranian Fajr-5 missiles, M-600 rockets, Zelzal-2 missiles, short-range M75 rockets and Katyushas, Defense News reported.

A senior Israeli Air Force officer stated the primary threat from Hezbollah’s weapons arsenal relates to the terror group’s acquisition of missiles with larger warheads capable of reaching further distances.

Israel estimates that Hezbollah’s weapons stockpile consists of more than 100,000 missiles—17 times the amount it possessed a decade ago, when the United Nations adopted Security Council Resolution 1701 to end the Second Lebanon War.