Israel will respond with a nuclear attack if it is attacked by nuclear weapons; so said Ben Guryon. Israel will use nuclear weapons in a desperate situation; and there is no doubt, as Golda Mair almost did in the war with Egypt. I doubt that a gas attack would trigger a nuclear attack; it depends on how successful it proves to be. Israel's enemies have to calculate, a nuclear attack by Israel would destroy them and that is Israel's great strength. Moreover Israel has fusion bombs and Iran can only have wet dreams about such weapons.
In Bahrain, 2 police officers killed, 6 wounded in bombing (AP)
from the article: Israel's enemies wouldn't dare launch chemical attack, Barak says