Danon said "Israel is not interested in escalation, but under no circumstances will we allow Iran to establish a military presence in Syria whose goal is to attack Israel and to deteriorate an already fragile situation in the region".
There have been no Israeli casualties.
Granted, Israel has said it doesn't intend to intervene in Syria's civil war, and that its operations are aimed exclusively at targets that pose a threat to its own citizens. Iran launched 20 rockets at Israel, which was met by a massive Israel Air Force response. The Observatory said the attacks killed 23 fighters, including five Syrian soldiers.
"The global community must prevent the entrenchment of Iran's Quds Force in Syria", Netanyahu added. The military said air defense systems intercepted "the large part" of the incoming Israeli strikes.
Israel, meanwhile, has the backing of the USA, which has called Iran's attack provocative.
Mr. Conricus said Israel was not looking to escalate the situation but that troops will continue to be on "very high alert".
"This event is not over", he said. Iran's strategic intent is clear. It was not immediately clear what was hit.
Among the first in the Arab nations, Bahrain's Foreign Minister Sheikh Khalid al Khalifa, also backed Israel.
Iran made no comment about the rocket fire. One TV station, Beirut-based Al-Mayadeen, said at least 50 missiles were fired from Syria at Israeli forces in the Golan Heights.
The targets were Israeli military positions - not civilian areas. It first intervened in the war to help defend Assad against Syrian rebels and later helped Syrian government forces against the Islamic State.
"The United States condemns the Iranian regime's provocative rocket attacks from Syria against Israeli citizens, and we strongly support Israel's right to act in self-defense". "Syrian missile batteries fired surface-to-air missiles at us and we hit them".More news: Android P's Navigational Moves Strangely Similar to iPhone X's
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Israel has neither confirmed nor denied most of the airstrikes. Israel responded by attacking anti-aircraft positions in Syria, and an Israeli warplane was shot down during the battle.
Iranian forces moved into Syria after the outbreak of the Syrian civil war in 2011 to back the forces of President Bashar Assad.
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Israel, too, may feel emboldened by US President Donald Trump s decision this week to withdraw from the 2015 Iran nuclear deal.
By Thursday morning, the Israeli Air Force had destroyed "nearly all" of Iran's military infrastructure in Syria, according to Israel's defence minister, Avigdor Lieberman. But Israel and Russian Federation have maintained close communications to prevent their air forces from coming into conflict.
He noted that in contacts with the leadership of both countries, including a meeting Wednesday between Netanyahu and Russian President Vladimir Putin in Moscow, "we underlined the necessity of avoiding any actions that might be mutually provocative".
"I informed President Putin that it's the proper of each state, definitely the best of Israel, to take the required steps to be able to defend itself from this aggression", Netanyahu stated, referring to Iran's presence in Syria.
The alleged Iranian attack last night - I say alleged because at this stage there is no confirmation from Iranian sources as to the precise authors of the attack - involved a single and relatively short-range system, what appears to have been a multiple-barrelled rocket launcher.
While the documents' authenticity has not been challenged by Western governments and intelligence experts, critics said they added little to previous assessments that concluded that Iran mothballed its effort to develop nuclear weapons in 2003.
Conricus, the Israeli military spokesman, said the military focused on inflicting "long-term damage on the Iranian military establishment in Syria" and assessed "it will take a substantial time to replenish". "They are determined to do it and we are determined to prevent it".
The two sides have been on a collision course for months.