Israeli PM Benjamin Netanyahu says his country will defend itself "against any attack" after carrying out what appear to be its largest strikes on sites in Syria in decades.
Israel launched raids against Iranian targets after saying it had intercepted an Iranian drone crossing the Syria-Israel border.
Iran denies the allegation.
During the offensive an Israeli F-16 fighter jet was shot down by Syria air defences, crashing in northern Israel.
Its pilots ejected from the plane and were taken to hospital.
It is believed to be the first time Israel has lost a jet in combat since 2006.
Mr Netanyahu warned that Israel's policy to defend itself against "any attempt to harm our sovereignty" was "absolutely clear".
"Iran brazenly violated Israel's sovereignty," he said, adding: "They dispatched an Iranian drone from Syrian territory into Israel... Israel holds Iran and its Syrian hosts responsible."
Mr Netanyahu said Israel would oppose any attempt by Iran to entrench itself militarily in Syria.
But he also said during a meeting with military chiefs that "Israel seeks peace".
In other reaction:
- The US state department said it supported Israel's right to defend itself, blaming Iran for the confrontation
- In a phone call with Mr Netanyahu, Russian President Vladimir Putin stressed the need to avoid a "dangerous escalation". He has been supporting President Assad's government in Syria's civil war
- UN Secretary-General Antonio Guterres has called for an immediate de-escalation in the actions that he said threaten a "dangerous spill-over" across Syria's border
Israel's military says one of its combat helicopters downed an Iranian drone infiltrating Israel on Saturday. It tweeted footage of the incident.
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