TEL AVIV — The Arab town of Jaljuliya in central Israel was shocked on Sunday morning to learn that, according to the Israeli army, a local resident paraglided into Syria in order to join ISIS-affiliated rebel forces.

“Jaljuliya is a very normal city, we are within the Green Line, and we believe very strongly in coexistence,” said Ali Arar, a Jaljuliya resident. He said that he, like all of his neighbors, was surprised to hear of the news, since the man, whose name is still under an Israeli gag order, was “beloved by everyone in the village, and really respected everyone.”

The 23-year-old flier originally was thought to have been carried into Syrian territory by the morning’s strong winds, though military investigations later confirmed that the crossing via Israel’s northern border on the Golan Heights was intentional. Some reports on the Web sympathetic to ISIS claimed an “Israeli pilot” had been captured.

Witnesses in the Israeli-held Golan Heights uploaded videos to social media of Israeli drones and warplanes circling the area and dropping flares in what the military later said was an intensive search effort to reveal the man's place of landing.

On the Syrian side of the border, rebel groups said the man arrived in Quneitra province, a territory infested with a host of competing groups, including Syrian regime-affiliated militias, the Free Syrian Army, the Nusra Front, and the Yarmouk Martyrs Brigade, which is affiliated with the so-called Islamic State. The Yarmouk Martyrs Brigade, however, addressed rumors on its Facebook page, saying that it had not taken an Israeli man into captivity.

“We are constantly fighting ISIS, the Nusra Front and other terrorist organizations,” said Israeli Prime Minister Benjamin Netanyahu at a weekly government meeting on Sunday. “Yesterday, an Israeli civilian crossed our border in the Golan Heights into Syria to join the ranks of the enemy. We will act to nullify his citizenship. That is what is done in any such case. Whoever joins the ranks of the enemy to fight against Israel will not be an Israeli citizen.”

Some 40 Arabs, including citizens of Israel as well as residents of Israeli-held East Jerusalem, have gone to join the fight in Syria or Iraq, mainly entering through Turkey, according to the Shin Bet, Israel’s internal security service.

At least four are known to have died there, while at least 10 have returned to Israel, where they were immediately arrested. Two have originated from Jaljuliya, said residents, including one man who said that he went to deliver aid to refugees and was arrested upon his return; as well as another man who is still believed to be in Syria.

And while many of the older community leaders denounce ISIS and say they have pushed back against extremism in the village, community leaders say that high rates of unemployment and crime have nonetheless helped drive the local youth to seek further involvement both in the domestic and regional conflict.

This has been worsened by Israeli policies of discrimination and marginalization as well as a rising sense of extremism among Israel’s Jewish population, said Hosni Arar, director of the sports programs in the village.

In March, Israeli police reported that 19 cars in the village were attacked by the radical Jewish pro-settler movement known as “Price Tag,” which has vowed that every time Israel curbs Israeli settlement in the West Bank it will respond by attacking Palestinian persons and properties.

And while comparatively less than elsewhere, the recent wave of violence in Israel and the Palestinian territories has sparked protests in Jaljuliya, where teenagers and young people filled the streets to protest Israeli occupation and policies of discrimination against its Arab citizens.

Since the start of the Jewish New Year last month, a spate of Palestinian stabbings and shootings, followed by violent protests throughout the West Bank, have claimed the lives of 10 Israelis, and more than 50 Palestinians, a number of whom were reported to be assailants.

As the security situation continues to deteriorate with almost daily attacks, even Israeli Arab communities normally portrayed as examples of Arab-Jewish coexistence have witnessed demonstrations that have turned violent. In Jaluliya, a co-existence youth tennis program has been halted because the Jewish coach has been afraid to venture into the village, organizers said.

“People don’t just randomly get up and do this kind of thing, here or in any other part of the conflicted areas in the Middle East—this willingness to go over into the dark side which is ISIS, is fueled by the situation,” said Hosni Arar, adding that youth mobilization on the streets has also brought the regional conflicts to the fore, with many discussing the new roles for the United States and Russia in Syria.

“Jews are going into al Aqsa mosque with their shoes, which is not allowed, and when we see the United States helping Iran and the Shiites, that adds to all of it, since we are Sunnis here,” said Arar.

ISIS, for its part, has been eager to capitalize on the momentum of the Israeli-Palestinian conflict.

Last week, it released a rare video that apparently pointed to at least one Arab citizen of Israel in its ranks. The 16-minute clip—which YouTube removed because it violated the site’s terms—featured a masked militant with a rifle speaking fluent Hebrew against the backdrop of footage from the recent violence in the West Bank. In Hebrew, he praised the spate of Palestinian terror attacks which since last month have targeted Israeli soldiers and civilians and spurred anxiety throughout the country, and vowed that “not one Jew will be left in Jerusalem or around it...we will continue to eradicate this disease from the world.”

While ISIS maintains a network across North Africa and elsewhere in the Middle East, it has no known organized presence in Israel or in the Palestinian Territories, though experts say that an ISIS-inspired Salafi jihadi movement is growing in Gaza. According to a survey released last month by the Palestinian Center for Policy and Survey Research, a majority of Palestinians do not believe that ISIS represents true Islam, though in Gaza, 9 percent said that that ISIS does represent true Islam, as compared to 6 percent who said the same in the West Bank.

Last July, ISIS released videos encouraging Palestinians to attack Israelis, and to overthrow “the tyrants of Hamas” in the Gaza Strip because they are not extreme enough.

And while Israel has warily eyed the developments in Syria since the civil war broke out in 2011, Israel has officially maintained a policy of neutrality as long as ISIS has prioritized Shiites and other inter-Muslim rivalries.

“Israel now needs to identify if ISIS is setting its sights on Israel,” said Daniel Nisman, a security analyst with the Levantine Group. “Very similarly to the challenges faced by other Western countries, Israel is not used to tracking these kinds of communities, who are not necessarily religious people, and do not believe in Palestinian nationalism but in the caliphate, and who are often intertwined with mainstream society.”