BEIRUT/AMMAN: Fighters from Syria’s Al-Qaeda branch, the Nusra Front, have killed at least 20 Druze villagers, raising fear for one of Syria’s minorities as insurgents including Sunni Islamists gain ground against President Bashar Assad.

Druze in Lebanon and Israel have made separate appeals for their Syrian kin to be armed to defend themselves from groups such as Nusra and the more powerful ISIS, which has persecuted both minorities and fellow Sunnis.

The Druze faith, related to Islam, Christianity and Judaism, is practiced by 1.5 million people, mostly in Syria, Lebanon and Israel. It is deemed heretical by the puritanical school of Sunni Islam espoused by Al-Qaeda and by ISIS, whose bid to advance toward a Druze area of southern Syria have added to concerns.

The shooting in the northwest occurred in the village of Qalb Lozeh in Idlib province, where the Nusra Front is part of an insurgent alliance that has seized wide areas from government control since March.

The killings spiraled from a confrontation that began when Nusra Front members tried to confiscate the house of a villager who fought alongside government forces, the Syrian Observatory for Human Rights activist group reported.

The dead included elderly people and at least one child, the U.K.-based Observatory said. A member of the Nusra Front was also killed when villagers managed to seize a weapon from a fighter.

An account of the incident attributed to a Nusra Front fighter and published on a Twitter account used by its supporters blamed a villager who refused to relinquish the house to someone “in need.”

Syria’s state-run news agency SANA described it as a massacre. A Lebanese Druze spiritual leader condemned the shooting and warned against a slide into the “furnace of lethal strife.”

An advance of Islamist fighters toward the Druze heartland of Swaida raises the prospect of another group being drawn deeper into the 4-year-old civil war that has killed around a quarter of a million people and made 8 million homeless.

The Druze spiritual leader in Syria issued a statement Tuesday calling on everyone who could bear arms to join the government army, saying their service would be restricted to Swaida province, which was threatened by “impending danger.” The statement was posted on Facebook by pro-government activists.

Assad, himself a member of a minority sect, the Alawites, has enjoyed support from many Druze in his fight against an insurgency whose two most powerful groups, ISIS and Nusra, are Sunni Islamists.

In an interview with Al-Jazeera news channel last month, the Nusra Front leader said Alawites must change their beliefs and renounce Assad if they wanted to remain safe.

Assad’s opponents accuse him of manipulating sectarian fears to shore up his support base.

The Druze have a large presence in Swaida province near the border with Jordan and Israel, where insurgents have made big gains recently.

The insurgents there include both the Nusra Front and other rebels who do not share its jihadi ideology and say they are committed to a diverse Syria. Some of the groups are supported by Western countries and their Arab allies, who are bombing ISIS fighters while also opposing Assad.

In recent months, ISIS has also been trying to advance into Swaida from the east. Swaida city, mostly unscathed in the war, was struck by shells Thursday that killed one person, state television reported.

The president of Israel, home to a large Druze community, Wednesday expressed concern to the U.S. about the fate of the Syrian Druze, saying around 500,000 of them were under threat from Islamist militants in southern Syria.

A U.S. official said the Druze of Israel had raised the idea of arming the Syrian Druze with Israel, the United States and with Jordan.

Wi’am Wahhab, a Lebanese Druze with close ties to the Syrian government, Thursday urged all Druze to help their Syrian kin with “money, volunteers, weapons.” He also called on Assad to arm them.

By contrast, Walid Jumblatt, Lebanon’s most influential Druze politician and an Assad opponent, has told Syrian Druze to reconcile their differences with those in the south who support the war against the Syrian regime.

Bashar al-Zoubi, a southern rebel leader, said the rebel campaign was not sectarian. “Swaida was in the range of the opposition for two years and we did not hit it once,” he told Reuters via the Internet.