Israel is concerned over the possibility of Iran increasing its engagement in Syria and Syrian nonconventional weapons falling in the hands of the rebel coalition led by the Islamist militant group Hayat Tahrir al-Sham that took over the city of Aleppo last week.

For Israel's security system, the advancement of the rebels in Syria poses a significant dilemma. On the one hand, Syria under President Bashar al-Assad did not join the fight in Lebanon against Israel after Oct. 7, 2023, and a stable Syria is in Israel's strategic interest. On the other hand, Assad might need stronger support from Iran than he already receives in order to push back against the rebels — the kind of support that would inevitably bring about a more significant entrenchment of Tehran in the country. From the Israeli point of view, potential Iranian entrenchment in Syria is considered a major strategic threat.

"The collapse of the regime in Damascus would pose a threat to the whole region, including Israel," said Yehuda Balanga, who specializes in Arab affairs at the Department of Middle Eastern Studies at Bar-Ilan University. "We have seen that the collapse of the strong regimes in Libya and in Iraq brought about chaos and disintegration. If Assad falls, Syria could break apart, plunging even further into civil war, including right on Israel’s northeastern border," he told Al-Monitor.

Middle Eastern and African Studies professor Eyal Zisser of Tel Aviv University agrees with Balanga. He told Al-Monitor that Israel, like most other regional players, was surprised by the quick move of the rebels. Still, he noted that despite the traditional Israeli approach of preferring Assad — "the devil we know" — there are voices now saying that "the upsurge of the rebels created an opportunity to rid the region of the Assad regime." Will Israel assist the rebels against Assad? Zisser believes that for the moment at least, the Israeli leadership is not considering such a possibility.