The Israel-Syria border area, July 7, 2018. Photo: Reuters / Ronen Zvulun.er

Israel shot down a Syrian drone that penetrated its airspace on Wednesday, the Israeli military said, while Prime Minister Benjamin Netanyahu flew to Moscow for talks with Damascus’s biggest ally about a Syrian advance near the volatile frontier.

Air-defense sirens on the Golan Heights and close to the nearby Jordanian border were set off when a Patriot missile fired to intercept the drone, a military spokesman said. It was the second such incident in the area in as many months.

The drone, which had also overflown Jordan and appeared to have been unarmed and designed for surveillance, was downed near the Sea of Galilee at the Golan foothills in northern Israel, spokesman Lieutenant-Colonel Jonathan Conricus told reporters.

“We are still looking into why it crossed — whether it was on a military mission and crossed on purpose, or it strayed,” he said, while adding that the latter scenario was “not common.”

Israel has been on high alert as Syrian President Bashar al-Assad’s forces advance on rebels in the vicinity of the Golan. Israel worries that he could deploy troops or allow his Iranian and Hezbollah allies to set up emplacements near Israeli lines.

Russia is Assad’s big-power backer in the 7-year-old civil war. Netanyahu traveled to Moscow on Wednesday for talks with President Vladimir Putin, who in the past has turned a blind eye to Israeli strikes on Iranian and Hezbollah targets in Syria while making clear Russia does not want Assad’s rule endangered.

“We will discuss Syria, we will discuss Iran, we will discuss Israel‘s security needs,” Netanyahu told reporters before departing. “I very much appreciate the direct, unmediated and excellent contact that I have with the Russian president.”

Israel captured much of the Golan in a 1967 war with Syria and annexed the strategic plateau in a move not recognized internationally. It has threatened to open fire at any Syrian government forces that try to deploy in a demilitarized Golan buffer zone set up as part of a 1974 UN-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 44-year-old armistice arrangements.

“There should be no military forces in the area of separation other than those of UNDOF,” a UN 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, discussions predicated on a full or partial return of the Golan.

Netanyahu’s government has made clear it would not now cede the plateau and has been lobbying for US 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.