JERUSALEM—Although Israel has repeatedly declared its determination not to get sucked into the civil war raging across the border with Syria, Defense Minister Moshe Yaalon admitted Monday that the country was in fact doing more than just cheering on the good guys.

In a briefing to Israeli diplomatic reporters, Yaalon acknowledged that Israel was helping out selected rebel groups operating in Syria near the border of the Golan Heights. "We’ve assisted them on two conditions—that they don’t get too close to the border and don’t let Islamic extremists get too close and that they don’t touch the Druze."

Some 130,000 Israelis are members of the Druze sect, an offshoot of Islam. Since the Syrian civil war began four years ago, Israel’s Druze have been concerned about the fate of their 600,000 brethren living in Syria, particularly those living in a village two miles away, Khader, easily visible from the border. Last week, mortar rounds could be seen exploding about a mile from the village where a battle was being fought between the Syrian army and the Free Syrian Army rebels.

The rebel groups being assisted by Israel include the Free Syrian Army, regarded in the West as the most moderate and stable of the parties involved in the conflict. It is a key player in the area adjacent to the Golan. In a recent interview on Israel Television, several of the Syrian fighters in Israeli hospitals spoke in terms of high praise of the Jewish state, which they had only known before through the prism of Syrian propaganda.

Yaalon did not specify what kind of assistance Israel is offering these quasi-allies. It is known that it includes medical treatment. Well over 1,000 Syrians, both fighters and civilians, brought to a field hospital Israel has erected on the border have been treated there and many, requiring more serious care, are taken to hospitals inside Israel. Israel is also believed to have provided common humanitarian care—clothing, food, blankets—to Syrian villages in the area.

What is not known is whether assistance includes weapons and ammunition. Rebel groups in the area are presumably being supplied with weapons from across the Jordanian border, not far to the south.

Yaalon was highly critical of Druze activists in the Golan Heights villages who ambushed an Israeli military ambulance last week, pulled out two wounded Syrians inside and beat one of them to death. The defense minister said those involved had acted "irresponsibly" and could bring disaster upon their brethren in Syria who might become revenge targets because of the Golan lynching.