Israeli Prime Minister Benjamin Netanyahu says Israel will never let Iran establish a military presence inside Syria.
Netanyahu made the vow during a telephone call Wednesday with Russian President Vladimir Putin.
Netanyahu's office gave little information about the call. But a Kremlin statement said Putin talked about the importance of maintaining Syria's sovereignty and said Israel should not take any action that threatens its security.
The Netanyahu-Putin phone call came on Israel's annual Holocaust memorial day, when the country pauses to remember the 6 million Jews slaughtered by the Nazis in World War II.
"Events of recent days teach that standing up to evil and aggression is a mission imposed on every generation," Netanyahu said at Israel's Yad Vashem Holocaust memorial. "We saw the swastika the rioters waved on the Gaza fence. We saw the Syrian children slaughtered by chemical weapons. Our hearts were torn from the horrific images."
Netanyahu also said Iran should not test Israel's "resolve" as he let the Iranian people know that Israel is not their enemy, but the "regime of tyrants" in Tehran is.
"When this regime disappears from the world, and it will disappear eventually, our two ancient peoples — Jews and Persians — can live again in cooperation and brotherhood," he said.
Israel is on high alert for possible Iranian retaliation after an Israeli airstrike on a Syrian air base Monday.
The airstrike was launched in response to an alleged Syrian chemical attack on a Damascus suburb Saturday that killed more than 40 civilians and injured hundreds.