MAJDAL SHAMS, Israel — When an ambulance rolled through Druze villages near the Israeli-Syrian border last month, it was met by an angry mob of stone-throwing protesters shouting that they’d been betrayed by Israel. Surrounding the emergency vehicle, they said Israel’s government is giving medical treatment to Islamist fighters who are now threatening to kill their Druze brethren in Syria. The mob opened the doors of the ambulance and dragged out the two patients inside, killing one of them.

Druze community leaders deeper inside Israel condemned the episodes as vigilantism, but in the Golan Heights, many Druze fear an imminent attack against their kin in Syria at the hands of the Nusra Front—an al Qaeda offshoot—which is believed to be leading a wider offensive to capture the traditionally pro-regime southern province.

The Druze are members of an esoteric and secretive sect rooted in Shia Islam, and are seen by ISIS and other Sunni radicals as heretical. They are a minority of just over 1 million in Syria, Jordan, Lebanon, and Israel. Except in the Golan Heights, where most have refused Israeli citizenship, the Druze men in Israel have served in large numbers in the Israeli army, most famously in elite combat and reconnaissance units along Israel’s borders.

While there is no evidence the Israeli government or its intelligence services are in direct contact with Nusra, for the Druze the distinctions among the Syrian opposition factions make little difference. The Druze on the far side of the border traditionally have supported the Assad regime, which now appears to have forsaken them. The motley rebel forces, which may well include Nusra, are closing in.

Since the Syrian civil war erupted more than four years ago, Israel has officially declared its policy to be non-intervention. But, reports by the United Nations buffer force on the Golan Heights, known as UNDOF, show that Israel has consistently maintained lines of communication with the Syrian opposition.

The UN has observed multiple incidents since early 2013, in which “armed individuals crossed the ceasefire line, approached the technical fence and at times interacted with IDF [members of the Israel Defense Forces] across the ceasefire line in the vicinity of United Nations observation. In some instances, wounded individuals were handed over from the Bravo [Syrian] side to the Alpha [Israeli] side,” according to a report issued in March by the UN peacekeepers on the scene.

There is also documentation of what may be weapons transfers between the IDF and members of the Syrian opposition. One report provided details of the evening of January 20, 2015, in which “UNDOF observed two trucks crossing from the Bravo [Syrian] side to the Alpha [Israeli] side, where they were received by IDF personnel. The trucks were loaded with sacks before returning to the Bravo [Syrian] side.” On another occasion trucks with anti-aircraft guns parked near the fence on the Syrian side, but the terrain blocked the view of UNDOF observers so they could not determine the extent of “interaction between individuals on each side of the line.”

These may be prudent contacts to keep Israeli intelligence services informed about what is going on in the horrendous war next door. But the Druze in these parts think there is more to them than that, and they do not believe these secretive contacts are meant to help their brethren across the line.

Israel maintains that it has dealt only with the Free Syrian Army, which has Western backing but has struggled to take the kind of military initiative seen by Nusra or, worse still, by the so-called Islamic State. Members of the multitude of Syrian rebel factions often move from one group to another and have shifting loyalties. (Imagine a jigsaw puzzle with pieces that sometimes allied and joined together—and sometimes attacked and destroyed each other. Now look at it through a kaleidoscope. That’s the Syrian opposition.) As a result many analysts doubt the Israeli government’s claim that it is steering clear of Nusra. Even if that’s its intention, the lines are terribly hard to draw.

The Israeli media regularly refer to the rebel groups’ constant contact with the IDF. Israeli journalist Ehud Yaari writes of “frequent secret meetings reportedly held in Tiberias,” but “only a modest amount of weapons have been provided to them, mainly rocket-propelled grenade launchers.”

While the IDF originally claimed to aid only unarmed opposition members, that claim is now ludicrous. “Today in Syria no man who respects himself would be unarmed,” Major Haim Mizrahi, a commander of the Golani reconnaissance unit, told Israel’s Channel 2 last month, as he drove to the border in the dead of night to facilitate the transfer of wounded Syrians to Israeli hospitals.

All this background has made the reported medical treatment of more than 1,600 Syrians in Israel an extremely sensitive issue among the Druze minority community, many of whom work as doctors at northern Israeli hospitals.

While the IDF originally promoted the humanitarian aspects of such treatment and allowed press to interview Syrian children given life-saving care at Israeli hospitals, army officials have gradually revealed that fighters are being healed along with the women and children.

Ayoub Kara, a Druze Knesset member with the right-wing Likud party, says that Israeli links to the Syrian opposition give it leverage on the rebels and that may be Israel’s best means of protecting the Syrian Druze just over the border. Kara, the highest-ranking Druze in the Israeli government, has discussed the situation extensively with Prime Minister Benjamin Netanyahu, who recently announced for the first time in more than four years of Syrian war that he will “do what is necessary” both to protect the Druze in Syria and to keep Islamist radicals like the Nusra Front and ISIS away from Israel’s border.

In a very nuanced and very gray set of relationships, Israel’s intercourse with the rebels is possible in part because the southern Nusra Front is known to be more moderate than the northern branch, says Daniel Nisman, president of the Levantine Group, a geopolitical risk consultancy in Tel Aviv.

“This is an ongoing relationship with locals who Israel was probably working with before, people who just joined the rebels because that’s where the money is, unlike ISIS that moved into the area from outside,” he says.

But for the Druze in Israel, whatever plan there is for protecting their brethren is not taking shape nearly quickly enough. They have grown increasingly anxious over the past three months as the Assad regime supported by many Syrian Druze has suffered a string of defeats and has increasingly withdrawn from the south to replenish its forces in other parts of the country.

Families at a lookout point gaze through binoculars to examine the nearby village of Hader, which has been surrounded almost completely by rebel forces since last month. According to some accounts, more than 100 men have already died in the clashes with the rebels.

Druze community leaders here say that they have sent more than 10 million shekels ($2.6 million) to their families, via Jordan, so that they can buy weapons off the flourishing arms trade route there.

Hader, once a serene agricultural town of about 12,000 inhabitants, and historically allied with Bashar al-Assad, is also strategically critical, say security analysts. Its capture would enable the opposition to build a continuous supply route between southern Syria and the decisive northwestern Qalamoun region near Damascus.

Here, tit-for-tat shelling and gunfire has been continuous over the past weeks, with the rebels on one hilltop and the residual regime forces on another, a Druze IDF officer tells the crowd. Last month, Israeli tanks began to position themselves near the border, prepared to intervene if the need arises.

Naim, a resident of Majdal Shams who asks that his full name not be used out of concern for his relatives in Syria, says he has faith that his brothers will be victorious in their anticipated battle against the rebels. He says that his cousin has joined thousands of other men from the village in intense training and is now prepared to fight. Naim’s cellphone buzzes with a text from his cousin: “The Nusra Front is getting closer.” He then hears a resounding boom and sees a plume of gray smoke rise just a few miles north of the village.

Hader’s immediate enemy is the Nusra Front, although the Druze say that a number of Syrian militant groups pose a threat to their people.

The community throughout the region was shaken to the core in June when 20 Druze villagers were massacred far from Israel in the northern Syrian province of Idlib at the hands of the Nusra Front. And while the Nusra Front said the incident was the fault of rogue members who would be tried in sharia court, many residents in places like Hader and Sweida saw it as confirmation that the Assad regime is deserting them and leaving them to be slaughtered.

Druze in the Golan have taken to the streets to call for protection by both Israel and the international community against what they worry could translate into genocide for their minority group.

Israel is a “humanitarian” country, says Druze IDF Brigadier General Maada Hasbani, but it also has a longstanding “blood pact” with its 120,000-strong Druze minority. If Israel truly wants to help the Druze to protect themselves, he says, it will need to help restock their dwindling weapon supply.

“Israel knows what is a Holocaust and we trust that it will, in the moment of truth, make the right decisions in order to protect the Druze of Syria from this real risk of annihilation,” he says.

Because many have been trained in Assad’s army, the Druze in the southern Quneitra province near Israel are prepared to defend themselves, explains Majdal Shams Mayor Doulan Abu Saleh.

“The Druze in the Golan have begun to understand that there is life after Assad, that it’s only a matter of time,” he says. “We, the Druze with Israel’s help, must begin to look toward the future situation. There is no one else to do this for us.”