Jerusalem (AFP) - Israel issued stark warnings on Sunday over Iran's presence in neighbouring Syria after a confrontation threatened to open a new and unpredictable period in the country's seven-year civil war.

Israel carried out major air raids in Syria on Saturday, including against what it described as Iranian targets -- the first time it had publicly acknowledged doing so since the war began.

The raids came after an Israeli F16 fighter was shot down by Syrian air defences. The pilots survived, but it was Israel's first loss of a warplane in battle since 1982.

"We inflicted on Saturday a heavy blow to Iranian and Syrian forces," Prime Minister Benjamin Netanyahu said at the start of Sunday's cabinet meeting.

"We made clear to everyone that our rules of engagement will not change in any way. We will continue to harm anyone who tries to harm us. This was our policy and this will remain our policy."

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Other Israeli ministers spoke of refusing to accept Iran entrenching itself militarily in Syria, as Netanyahu has said repeatedly. Tehran denies it is doing so.

While several analysts said they did not expect a further escalation in the coming days, some spoke of the possibility of the Syrian war entering a new phase.

Syria has become more emboldened to try to stop Israeli strikes inside the country, while Israel wants to maintain its ability to operate there when it sees fit, said Ofer Zalzberg of the International Crisis Group think tank.

Israel has sought to stay out of direct involvement in the Syrian war, but it acknowledges carrying out dozens of air strikes there to stop what it describes as deliveries of advanced weapons to Lebanese Shiite group Hezbollah.

Israel fought a devastating war in 2006 with Hezbollah, which along with Iran and Russia backs the Syrian regime in the conflict.

"I think this incident is more likely to be contained because fundamentally it is a gradual attempt to renegotiate the so-called rules of the game," Zalzberg said, adding that Russia should mediate.

Witnesses said Israel had deployed a missile defence system in the Israeli-occupied Golan Heights near the demarcation line with Syria on Sunday morning.

- 'Playing with fire' -

Saturday's events began with Israel shooting down what it described as an Iranian drone that had entered Israeli airspace from Syria -- which Tehran has denied.

On Sunday, Israeli military spokesman Jonathan Conricus alleged the drone was a copy of a US model captured by Iran in 2011. He said the conclusion was made from an analysis of the drone's debris.

Israel responded on Saturday with a raid on what it said was the Iranian control systems in Syria that sent the drone.

During that raid, the Israeli F16 met heavy Syrian anti-aircraft fire and was hit, Israeli Air Force Brigadier General Amnon Ein Dar told army radio.

The pilots ejected and the plane crashed inside Israel. One crew member was severely wounded, but his condition was said to be improving on Sunday.

Israel then carried out what it called "large-scale" air strikes inside Syria, including against what it described as Iranian targets.

Conricus warned on Saturday that Syria and Iran were "playing with fire", but stressed that Israel was not seeking an escalation.

"This is the most blatant and severe Iranian violation of Israeli sovereignty" in recent years, Conricus said.

Iran dismissed Israeli "lies" and said Syria had the right to defend itself against Israeli attacks.

Iranian foreign ministry spokesman Bahram Ghasemi said "Iran does not have a military presence in Syria, and has only sent military advisers at the request of the Syrian government."

Russia stressed the need to "avoid any measure that could lead to a dangerous escalation".

United Nations Secretary General Antonio Guterres called for an immediate de-escalation.

Netanyahu spoke with both Russian President Vladimir Putin and US Secretary of State Rex Tillerson after Saturday's confrontation.

Washington backed Israel and blamed Iran for the escalation.

Tillerson on Sunday begins a Middle East tour that will take him to Jordan, Turkey, Lebanon, Egypt and Kuwait.

Netanyahu has met regularly with Putin in recent months in a bid to convince Russia to keep Iranian forces away from Israeli territory.

Russia and Israel have also established a hotline to avoid accidental clashes in Syria.

Israel is technically at war with Syria and occupies a swathe of the Golan Heights that it seized in the Six-Day War of 1967 and later annexed in a move never recognised by the international community.