JERUSALEM _ The Israeli military said it shot down a Syrian fighter jet that crossed into Israeli airspace Tuesday as tensions flared along the volatile border between the two countries.
News of the downed warplane came shortly after the Syrian government announced that its forces have taken back some positions near the southwestern frontier with the Israeli-occupied Golan Heights that have been under the control of insurgents for seven years.
Syrian state media said the jet was taking part in the fight to drive militants loyal to the extremist group Islamic State from the Yarmouk basin, a sliver of land bordering the Golan Heights.
The official Syrian Arab News Agency portrayed the shoot-down, which it said took place over Syrian territory, as evidence of Israeli collusion with militants _ a frequent claim by Syrian officials, and one which Israel rejects.
The Israeli military said the Syrian Sukhoi fighter jet penetrated about a mile into Israeli airspace before two Patriot missiles were launched at the plane, which crashed in the southern part of the Syrian Golan Heights.
Lt. Col. Jonathan Conricus, an Israeli military spokesman, did not say whether the Syrian plane had deliberately crossed into Israel but said an "irregular amount of aerial activity" had been observed on the Syrian side of the border during the course of the day.
Israel issued numerous warnings through different channels and in different languages _ including a hotline set up between Israeli and Russian officers to avoid accidentally trading fire over Syria _ to make sure no planes breached Israeli airspace, he said.
Israel has avoided taking sides in the war in Syria, now in its eighth year. But it has repeatedly stated that it won't tolerate any violation of a 1974 agreement that established a demilitarized zone between Israel and Syria _ whether by Syrian President Bashar Assad's government or its allies, Russia and Iran.
Prime Minister Benjamin Netanyahu called Tuesday's incident "a gross violation" of the agreement, reached after Israel captured the Golan Heights from Syria in 1967.
"We will not accept any such penetration of, or spillover into, our territory, neither on the ground nor in the air," the Israeli prime minister said in a video statement.
Tensions have escalated in the region since the Syrian government launched a campaign last month to reclaim areas in the southwest of the country that border Jordan and Israel.
On Tuesday, the Syrian state-run broadcaster Al-Ikhbariya reported that government forces had reached a fence marking the beginning of a United Nations-monitored buffer zone between Syria and Israeli forces in the Golan Heights.
The station broadcast footage from a correspondent who said he was standing about 40 yards from the fence. The camera then panned to what the correspondent said was a U.N. post on the other side of the fence and an Israeli post about 400 yards away.
It was the first time that government forces have been in control of positions along the Golan Heights since 2011, when the uprising against Assad began.
