The Israeli military said it had been informed in advance of a massive cruise missile strike on a Syrian airbase, the first US operation against the Damascus regime in six years of civil war.
"In both word and action, President (Donald) Trump sent a strong and clear message today that the use and spread of chemical weapons will not be tolerated," a statement from Netanyahu's office said.
"Israel fully supports President Trump's decision and hopes that this message of resolve in the face of the Assad regime's horrific actions will resonate not only in Damascus, but in Tehran, Pyongyang and elsewhere."
Israeli President Reuven Rivlin said the "clear and determined steps" taken "constitute a fitting and appropriate response to such unthinkable brutality."
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There had been international outrage over Tuesday's suspected attack that killed dozens of civilians but Moscow stood by its Damascus ally and warned of the negative consequences of any military action.
As a result, a UN Security Council debate on a Western-drafted resolution was again delayed on Thursday amid Russian insistence that the chemical weapons that caused the deaths had been stockpiled by jihadists on the ground and released by a conventional strike.
Israel has repeatedly struck alleged weapons convoys in Syria they claim are bound for Lebanese Shiite militant group Hezbollah.
However it has been reluctant to be dragged into the civil war and has rejected calls for a more substantial intervention.
After Russia entered the war in support of its ally President Bashar al-Assad in late 2015, Moscow and Israel agreed to coordinate on their actions to avoid accidents.
Netanyahu said at the time that the Israeli strikes targeted Hezbollah and warned the army would do so again if necessary.