Israel has also seen regular spillover fire from the Syrian conflict and acknowledges carrying out dozens of air strikes to stop advanced arms deliveries to its arch-foe Hezbollah.

Hermes 900 drone test in the Golan Heights. AFP
Hermes 900 drone test in the Golan Heights. AFP (AFP)

Israel shot down a "Syrian spy drone" over the Golan Heights on Saturday, the Israeli military said.

The drone was downed with a Patriot interceptor missile over the Golan demilitarised zone that has separated Israeli and Syrian forces since the ceasefire deal that followed their 1973 war.

The military initially said the UAV was Russian-manufactured but offered no evidence. 

A military source later said it was unclear whether the UAV was indeed Russian-made.

"It was a reconnaissance UAV (unmanned aerial vehicle) and not an attack UAV and we are checking whether there is any connection to Iran and Hezbollah," military spokesman, Lieutenant-Colonel Jonathan Conricus, said.

Israeli Defence Minister Avigdor Lieberman said Israel viewed the incident gravely and would respond to any provocation.

"We hold the Syrian regime responsible for any firing or breach of sovereignty and call on it to hold back all players active in its territory," Lieberman said in a statement.

Russia intervened in the civil war on behalf of Syrian regime leader Bashar al-Assad in 2015, joining a de-facto alliance with Iranian forces, Lebanese Hezbollah and other Shia militias helping Damascus beat back Daesh and other insurgent groups.

Israel fears an eventual Assad victory could leave Iran with a permanent garrison in Syria, extending a threat posed from neighbouring Lebanon by the Iranian-backed Hezbollah and has been lobbying Russia and the United States for reassurances that Iranian and Hezbollah forces will not be allowed to deploy near its border or set up bases within Syria.

"We will not allow the Shia axis to establish Syria as its forefront base," Lieberman said.

Israel seized 1,200 square kilometres of the Golan Heights from Syria in the Six-Day War of 1967 and later annexed it in a move never recognised by the international community.

The area has seen spillover violence from the Syrian civil war. Israel has at times fired to foil what it deemed deliberate cross-border attacks and has struck suspected Hezbollah arms shipments around 100 times in Syria during the civil war.

For its part, Russia has set up a military hotline to prevent warplanes or anti-aircraft units clashing accidentally over Syria.

Source: TRTWorld and agencies