Islamist rebels participated in fighting against Assad forces Saturday on the Syrian border with Israel, according to a new video released by the opposition.

Fighting in the town of Breiqa, situated on the 1974 ceasefire line between Syria and Israel, and just 2.5 kilometers (1.5 miles) from the Israeli agricultural village of Alonei Habashan, began in the early hours of Saturday.

Fifteen Syrians injured in the fighting were evacuated to Israeli hospitals on Saturday, the highest number of Syrians to enter Israel in a single day so far.

During the fighting in Breiqa Saturday, six mortars fired from Syria landed inside Israel, causing no damage or injuries. Israel retaliated by firing a Tamuz missile at the Syrian military post from which the fire emanated.

It was the second time Israel retaliated with the advanced camera-guided missile to fire coming from Syria. In May, Israel hit a Syrian army post that shot at an IDF patrol jeep along the border.

A video published on YouTube by the al-Furqan Brigades, a Free Syrian Army unit fighting on the Golan Heights, displayed footage of a gun battle raging between regime fighters and an opposition force including the Jihad Battalions and the Salafist Ahrar al-Sham movement, in addition to the Furqan Brigades, who reported the death of five fighters and the injury of others in battles with regime forces.

In March, members of the al-Furqan group were filmed close to Israel’s border watching and studying IDF patrols along the border.

Earlier that month, Syrian rebel forces captured a military intelligence facility close to the border with the Golan Heights, in the town of Shajara some eight kilometers (five miles) from the ceasefire line between Israel and Syria.

The attitude of rebel fighters on the Golan Heights toward Israel remains largely unknown. Few indications have so far emerged of overtly Islamist forces combating the regime so close to Israel.

In July, a spokesman for the Yarmouk Martyrs Brigade — the militia that kidnapped UN peacekeepers in March and May – told The Times of Israel that his fighters had no quarrel with Israel and were focused on combating Bashar Assad’s forces only.

Emerging in the northwestern province of Idlib in late 2011 and led by Hassan Aboud, Ahrar al-Sham (the Free Men of Syria) has grown to become the largest fighting force within the Syrian Islamic Front, with an estimated 10,000-20,000 fighters.

Ahrar al-Sham captured the city of Raqqa in north-central Syria in early March, together with al-Qaeda affiliate al-Nusra Front. Unlike al-Nusra, however, Ahrar al-Sham was not placed on the US list of terror organizations.

Aaron Kalman contributed to this report.