Israel's defence minister has instructed troops to prepare to stay for winter on the peak of Mount Hermon, which sits on the border between Syria, Lebanon and a UN demilitarised buffer zone in the Golan Heights.
The announcement comes after Israel seized control of the zone on 8 December after the fall of Syrian President Bashar al-Assad.
Defence Minister Israel Katz's office said in a statement that "due to what is happening in Syria, there is enormous security importance to our holding on to the peak".
Katz posted a picture on X showing Prime Minister Benjamin Netanyahu using binoculars with the words: "Overlooking the Syrian peak of Mount Hermon, which returned to Israeli control after 51 years."
The UN has called on Israel to withdraw from the buffer zone, which sits between Syria and the Israeli-occupied Golan Heights.
UN Secretary General António Guterres said in a statement that he was "deeply concerned by the recent and extensive violations of Syria's sovereignty and territorial integrity".
The UN has said Israel is in violation of a 1974 disengagement agreement between Israel and Syria that established the buffer zone.
Israel has said the 1974 disengagement agreement "collapsed" with the fall of the Syrian government.
The summit of Mt Hermon is on the Syria-Lebanon border. The UN base near the summit is within the buffer zone.
The Golan Heights is a plateau about 60km (40 miles) south-west of Damascus.
Israel seized the area from Syria in the closing stages of the 1967 Six-Day War and annexed it in 1981. The move was not recognised internationally, although the US unilaterally did so in 2019.
After rebel forces overthrew the Assad regime in Syria, the Israel Defense Forces (IDF) seized control of the buffer zone and moved into new positions in the Golan Heights, including the top of Mt Hermon.
The statement from Katz's office said that "everything must be done to ensure the IDF's readiness on site in order to allow the fighters to stay there in the severe weather conditions".
Guterres said on Thursday that the 1974 agreement "remains in force" and condemned any actions inconsistent with it. He called on its parties to uphold their obligations, including "by ending all unauthorised presence in the area of separation".
Guterres also said he was "particularly concerned" about the hundreds of Israeli airstrikes on several locations in Syria.
The IDF said its air force and navy conducted more than 350 strikes this week, targeting Syrian military assets.
Israel said it was acting to stop weapons falling "into the hands of extremists".