JERUSALEM/MOSCOW (Reuters) - Israeli Prime Minister Benjamin Netanyahu told Russia on Wednesday that Israel would not seek to topple its ally, Syrian President Bashar al-Assad, but Moscow should encourage Iranian forces to quit Syria, a senior Israeli official said.

Netanyahu conveyed the message in talks with Russian President Vladimir Putin, the official said, just hours after Israel shot down what it described as a Syrian drone that had penetrated its airspace, underscoring the frontier’s volatility.

Israel has been on high alert as Assad’s forces advance on rebels in the vicinity of the Golan Heights, much of which Israel captured from Syria in 1967 and annexed in a move not recognized internationally. Israel worries Assad could let his Iranian and Hezbollah reinforcements entrench near Israeli lines or that Syrian forces may defy a 1974 Golan demilitarization.

“They (Russia) have an active interest in seeing a stable Assad regime and we in getting the Iranians out. These can clash or it can align,” said the Israeli official on condition of anonymity.

“We won’t take action against the Assad regime,” the official quoted Netanyahu as telling Putin in Moscow.

David Keyes, a Netanyahu spokesman, denied that the prime minister made that statement to Putin.

Asked to summarize Israeli policy on Syria, Keyes said: “We don’t get involved in the civil war. We will act against anyone who acts against us.”

The Israeli official who requested anonymity said Russia was working to distance Iranian forces from the Golan and had proposed that they be kept 80 km (50 miles) away but that this fell short of Israel’s demand for their full exit along with that of Tehran-sponsored militias.

Russian officials had no immediate comment on the meeting.

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Since turning the tide of Syria’s civil war by intervening militarily in 2015 on Assad’s behalf, Russia has turned a blind eye to scores of Israeli air strikes against Iranian and Hezbollah deployments or arms transfers, while making clear it wanted Assad kept immune.

Israel said a Syrian drone, apparently unarmed and designed for surveillance, entered its airspace and was downed with a Patriot missile near the Sea of Galilee on Wednesday. The interception set off sirens on the Golan and nearby Jordanian border.

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“We are still looking into why it crossed - whether it was on a military mission and crossed on purpose, or it strayed,” said Lieutenant-Colonel Jonathan Conricus, an Israeli military spokesman. He said a stray drone was “not common”.

Israeli cabinet ministers threatened this week to fire on Syrian forces that enter the Golan buffer zone set up as part of a 1974 U.N.-monitored armistice. The United Nations last month renewed the mandate of its Golan observer force UNDOF and on Wednesday called on all parties to abide by the armistice.

“There should be no military forces in the area of separation other than those of UNDOF,” a U.N. spokesman said.

Israel has signaled openness to eventual ties with Assad, a tacit acknowledgement that he is re-consolidating power as he routs Syria’s rebels.

Under Assad family rule, Syria held direct negotiations with Israel in the United States in 2000 and indirect talks mediated by Turkey in 2008. Netanyahu’s government has made clear it would not now cede the Golan and has been lobbying for U.S. recognition of Israel’s claim of sovereignty there.

On June 24, Israel’s military said it launched a Patriot missile at an incoming drone from Syria, which turned away unscathed. A Syrian commander said the drone was engaged in local operations. On July 6, Israel struck a Syrian post that it said had shelled the Golan buffer zone.