The Israeli military has been on high alert as fighting inside Syria has pushed closer to Israel's northern border in recent weeks. As the civil war in Syria has shifted in favour of Assad, who is backed by forces from Iran and Russia, Israel has watched with alarm. Despite being technically at war with Syria, Israel says it has no issue with Syrian government forces returning to areas they held before the civil war - as long as forces linked to Iran are excluded.
That concern was the subject of talks between Israeli Prime Minister Benjamin Netanyahu and Russian Foreign Minister Sergei Lavrov during his visit to Israel yesterday. An Israeli official said the Russians had offered to enforce a 100km buffer zone inside Syria free of Iranian forces. However, Israel is demanding that Iranian troops fully withdraw.
"We made clear again that we would not accept an Iranian military buildup in Syria, not near the border and not beyond the 100km strip that the Russians are talking about," the official said.
The Israeli military has carried out more than 100 airstrikes in Syria in an effort to prevent Iranian entrenchment or the transfer of arms to its proxy, Hizbollah, and the jet downing was a reminder of the potential for escalation. Earlier this year, Israel shot down a drone that crossed into its airspace, saying it was armed and operated by Iranian forces inside Syria.
"Iranian military entrenchment in Syria is a red line for Israel. If it's 100km from the border or 120, it makes no difference for us," said Tzachi Hanegbi, Israel's Minister for Regional Cooperation. "They don't need to be close to us to harm us."
He said Israel has been working for more than a year to make Russia understand how "crucial" the Iranian issue is for Israel.
Lieutenant Colonel Jonathan Conricus, a spokesman for the Israeli military, said Israel's policy in Syria remains one of "noninterference."
"For the past few days we have seen movement of Syrian forces approaching the area close to our border, and all of our defensive systems have been on elevated readiness levels," he said. Today, warnings were issued through various "channels" as a heightened amount of aerial activity took place just over the boundary.
The plane, a Sukhoi 22 or 24, took off from the T-4 military base near Palmyra, he said. "From our perspective, this event has finished," he said. "It is not ongoing."
On Syrian state media, the attack was framed as an assault on the country's sovereignty. On several television channels, indignant guests claimed that the Israeli strike had targeted Syrian warplanes as they bombed Islamic State positions near Damascus.
In southwest Syria, only a few small pockets remain under opposition control as Assad's army nears the end of a months-long offensive.
Israel captured most of the Golan Heights, a strategic elevated plateau on its northern border, from Syria in 1967. A United Nations peacekeeping force was deployed in the region in 1974, when a demilitarised buffer zone was established. In 1981, Israel annexed the area it occupied.
