• UN chief concerned by Israeli strikes in Syria
• Mass rallies take place in Syria celebrating end of Assad regime
• 1.1m newly displaced in Syria: UN 

Israeli Defence Minister Israel Katz yesterday ordered the military to "prepare to remain" throughout the winter in the UN-patrolled buffer zone between Israeli and Syrian forces on the strategic Golan Heights.

Israel seized the demilitarized zone on Sunday, just hours after Syrian rebels swept president Bashar al-Assad from power.

Since then, the Israeli military has launched hundreds of air and naval strikes against Syrian military assets, targeting everything from chemical weapons stores to air defences to prevent them from falling into rebel hands.

"Due to the situation in Syria, it is of critical security importance to maintain our presence at the summit of Mount Hermon, and everything must be done to ensure the (army's) readiness on-site to enable the fighters to stay there despite the challenging weather conditions," Katz's spokesman said in a statement yesterday. Israel says it seized the buffer zone to defend itself.

US Secretary of State Antony Blinken yesterday told Turkey it was "imperative" to work against a resurgence of the Islamic State (IS) group in Syria following the fall of Bashar al-Assad.

His remarks came after meeting Turkish Foreign Minister Hakan Fidan in Ankara on the second leg of his Syria crisis tour following the fall of Bashar al-Assad's government. Blinken also pledged to work with Iraq against IS.

Meanwhile, mass rallies took place in Syria to celebrate the end of five decades of authoritarian rule by the Assad regime.

"I would like to congratulate the great Syrian people on the victory of the blessed revolution and I call on them to go to the streets to express their joy," said the leader of the rebels Abu Mohammed al-Jolani, who is now using his real name Ahmed al-Sharaa.

Israel's seizure of the buffer zone has triggered widespread international criticism, including from UN chief Antonio Guterres.

Guterres "is deeply concerned by the recent and extensive violations of Syria's sovereignty and territorial integrity," his spokesman Stephane Dujarric said in a statement on Thursday.

In a separate development, the United Nations humanitarian agency said Thursday that more than a million people, mostly women and children, had been newly displaced in Syria since rebels launched an offensive ousting president Assad.

"As of 12 December, 1.1 million people have been newly displaced across the country since the start of the escalation of hostilities on 27 November. The majority are women and children," the UN Office for the Coordination of Humanitarian Affairs (OCHA) said in a statement.