A ratcheting-up in hostilities between Israel and two of its neighbors Sunday speaks to an ongoing escalation of turmoil in the Levant.

Israel is now keeping a close eye on two of its volatile borders. In the north, military confrontations in the Golan Heights threaten to reignite dormant tensions between Israel and Syria. Down south,  retaliatory clashes between the Israeli Defense Forces and Palestinian militants in Gaza have been escalating by the day.

Israeli forces fired into Syrian territory on Sunday after Syrian weapons fire spilled into the contested Golan Heights, which has been occupied by Israel since 1967. The Israeli strike was meant as a warning; according to Reuters, Defense Minister Ehud Barak said Sunday that he had cautioned the Syrian regime, which is fighting to the death against rebels, to control its armed forces to prevent future mistakes.

“The message has certainly been relayed. To tell you confidently that no shell will fall? I cannot. If a shell falls, we will respond,” he said.

Though Israel wants no part in the Syrian conflict, it is interested in protecting the Golan Heights plateau that connects the two countries.

Golan was taken from Syria by Israel during the Six-Day War of 1967. Syria tried and failed to retake the territory in the 1973 war, after which a ceasefire was established. In 1981, Israel annexed the area in a unilateral move that has not been recognized by the international community. The countries are technically at war, though the Golan Heights has been relatively peaceful for decades.

The 700-square-mile territory is of strategic importance. The area is occupied by about 20,000 Israeli settlers, according to the BBC, along with 20,000 Syrians, most of whom belong to the Druze religious sect. From the plateau, where altitudes can exceed 9,000 feet, Syria’s capital city of Damascus is plainly visible at a distance of about 40 miles.

Precipitation in the Golan trickles down into Israel via the Jordan River, supplying a full third of the country’s water supply.

Thursday marked the third time in a week that Syrian forces had breached Golan Heights’ armistice line, but Sunday was the first time Israel has fired into Syrian territory since 1973.

The move raised fears that the Syrian conflict, which pits loosely organized rebel forces against the regime of President Bashar al-Assad, is upending stability in the region. The 19-month rebellion, which has claimed more than 36,000 lives according to opposition activists, has become an increasingly sectarian one that inflames Sunni-Shi’a across the Muslim world tensions and attracts extremist militants.

Turkey, Lebanon, Iraq and Jordan are struggling to accommodate Syrian refugees and contain spillover violence.

Israel is keenly aware of the threat posed by the Syrian turmoil, as the military made clear in a Sunday statement.

“The IDF has filed a complaint through the U.N. forces operating in the area, stating that fire emanating from Syria into Israel will not be tolerated and shall be responded to with severity,” it said.

Meanwhile, in southern Israel, clashes with militants in Gaza are intensifying. A Gazan missile strike against Israeli forces wounded four soldiers on Saturday. In response, the IDF initiated shelling that killed five Palestinians. This prompted a new round of rocket attacks from Gaza, which did not result in casualties. Israel then engaged in air strikes that killed one more Palestinian on Sunday.

Barak said the situation as under assessment, leaving open the possibility that a larger offensive against Palestinians militants may be in the works.

Analysts note that Israel’s coming parliamentary elections, slated for Jan. 22, might affect the government’s military calculations as it responds to threats from both Syria and Gaza.

But Barak dismissed those speculations.

“I don't think the elections have to have any effect on our response," he said, according to Reuters. "It shouldn't cause us to refrain from acting, it's not handcuffing us. But it shouldn't provoke us to take an opportunity to launch an operation."