The Israeli premier said a 50-year-old “disengagement agreement” between the two countries had collapsed and “Syrian forces have abandoned their positions”. As a result, he said, “I directed the IDF (military) yesterday to seize the buffer zone and the commanding positions nearby. We will not allow any hostile force to establish itself on our border”.

The announcement, which Netanyahu made while visiting the Israeli-occupied Golan Heights which abut the buffer zone, came after the military said it had deployed forces to the area.

Israel had already said the day before, as the Islamist-led rebels swiftly advanced across Syria, that its soldiers entered the UN-patrolled buffer zone to assist peacekeepers in repelling an attack. On Sunday, the army announced a troop deployment there, citing “the possible entry of armed individuals into the buffer zone”.

“Following the recent events in Syria… the IDF (military) has deployed forces in the buffer zone and in several other places necessary for its defence, to ensure the safety of the communities of the Golan Heights and the citizens of Israel,” a military statement said. Israeli forces “will continue to operate as long as necessary in order to preserve the buffer zone and defend Israel”, it added. The statement stressed that the Israeli military “is not interfering with the internal events in Syria”.

Since the rebel coalition, led by Islamist group Hayat Tahrir al-Sham, began its renewed offensive against government forces on November 27, Syrian government forces have left positions near the Israeli-held Golan, according to a war monitor.