A possible conflict with Iran is foremost in the minds of Israel's military planners. But the greatest threat to the offshore production platforms and other facilities, such as a mooted floating liquefied natural gas terminal, is widely seen as attacks by anti-ship missiles or suicide bombers in small boats packed with explosives.
One of the key decisions under consideration is whether to deploy missile interceptors on the offshore facilities. This stems from intelligence reports that Hezbollah in Lebanon, the Islamic Republic's leading proxy in the Arab world, has received anti-ship missiles from Iran's Revolutionary Guards.
Netanyahu's sharpening focus on protecting Israel's most important industrial infrastructure, not just the emerging gas industry, stems from the growing awareness that the country faces the threat of a multi-front bombardment on an unprecedented scale by missiles and rockets.
The military and the defense industry are racing to develop anti-missile systems that had long been ignored to create a four-layer defense shield. Two systems, the high-altitude, long-range Arrow to counter ballistic missiles and Iron Dome to intercept short-range missiles and rockets, are more or less in place.
But an advanced Arrow-3 system planned to hit Syrian or Iranian ballistic missiles beyond Earth's atmosphere and David's Sling to counter medium-range projectiles, are unlikely to become operational for at least another year.
The military "recently conducted an analysis of what would happen to the home front in a war," The Jerusalem Post reported.
"The analysis was based on missile attacks against Israel during the First Gulf War in 1990-91, the Second Lebanon War in 2006 and Operation Cast lead (against the Gaza Strip) in 2009, as well as on the type of missiles and rockets now in the hands of Hezbollah in Lebanon and Hamas in the Gaza Strip."
Israel's military planners say that "during a war, Hezbollah will try to hit military targets with its long-range rockets and would then shift its focus to infrastructure," the Post observed.
Israel's major gas fields, discovered in 2009-10, and new discoveries now under way, are considered high-priority strategic targets for missile attack as they will transform the Jewish state's economy in the coming decade.
They are already considered vulnerable to attack from Lebanon, which claims a large part of Israel's Leviathan field, with estimated reserves of 20 trillion cubic feet of gas, extends into Lebanese waters.
Hezbollah, a powerful military force armed and funded by Iran and Syria, has vowed to hit Israel's gas installations if the Jewish state "plunders" Lebanese assets.
A more distant threat comes from Turkey, a former key ally of Israel but now a bitter adversary. It opposes gas exploration by Cyprus, a Greek-dominated island north of Israel whose gas fields are believed to adjoin Israel's.
Israel and Cyprus plan to jointly export natural gas via an undersea pipeline to Europe via Greece, or build a $1 billion liquefied natural gas plant-terminal.
The Turks have considerable naval and air power, although, for the moment at least, the risk of military action on their part appears slight.
But in the volatile eastern Mediterranean, with Ankara's Islamist government determined to restore Turkey's regional leadership, and Israel bracketed between two old Arab enemies, Syria and Egypt, that are now in turmoil, renewed conflict cannot be discounted.
Israeli officials say Hezbollah, which used an Iranian anti-ship missile for the first time in its 2006 war with Israel to cripple a naval corvette, has a stockpile of C-704 anti-ship missiles that could be used against offshore gas facilities.
In March 2011, Israel's navy seized several C-704s among 50 tons of Iranian weapons destined for Gaza aboard a freighter in the Mediterranean.
Brig. Gen. Yaron Levi, a senior naval commander, recently cautioned that Hezbollah has warned that if Israel imposed a naval blockade on Lebanon, the Shiite movement would retaliate with missile attacks on Israeli targets at sea.
"You don't need to be a genius to know where our oil rigs are," Levi said.
Hezbollah's arsenal, he stressed, "covers all of Israel's ports, our economic waters and a large part of the shipping lanes to Israel."
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