ONCUPINAR (Turkey) • Thousands of Syrians braved the freezing cold at Turkey's border on Saturday after fleeing a regime assault that threatens a new humanitarian disaster, as Damascus warned Riyadh and Ankara not to send in troops.
The government said any uninvited foreign soldiers who enter Syria would go home "in a wooden coffin", following reports that Saudi Arabia and Turkey, which support rebel forces, could deploy troops.
Tens of thousands of people have fled fierce fighting as government forces backed by Russian air strikes advanced last week against rebels, severing the opposition's main supply route into the northern metropolis of Aleppo.
Turkey's Oncupinar border crossing, which faces Bab al-Salama inside Syria, remained closed on Saturday. The United Nations said some 20,000 people had gathered at Bab al-Salama but the governor of Turkey's Kilis border province, Mr Suleyman Tapsiz, said at least 70,000 may head for the frontier.
He said the displaced were being accommodated in eight camps on the Syrian side and that Turkey - already home to 21/2 million Syrians - was also able to take care of 35,000 refugees inside Syria.
Thousands have been sleeping in the open, at the border... And because the main rebel supply route between Aleppo and Turkey has been cut, the price of oil, foodstuffs and baby milk has shot up in the north of Aleppo province.
MR MAMUN AL-KHATIB, director of the pro-rebel Shahba Press news agency.
Turkish Foreign Minister Mevlut Cavusoglu said his country would keep its "open border policy" for Syrian refugees: "We have received already 5,000 of them; another 50,000 to 55,000 are on their way and we cannot leave them there."
According to the Britain-based Syrian Observatory for Human Rights, around 40,000 Syrian civilians have fled the regime offensive.
Thousands have been sleeping in the open, at the border and in the nearby Syrian city of Azaz, said Mr Mamun al-Khatib, director of the pro-rebel Shahba Press agency. "And because the main rebel supply route between Aleppo and Turkey has been cut, the price of oil, foodstuffs and baby milk has shot up in the north of Aleppo province."
The Observatory said 435 people have been killed since the regime offensive began last Monday, including 71 civilians, most of whom had died in Russian air strikes. Also killed were 124 regime forces, 90 militants from Al-Qaeda's Syria affiliate Al-Nusra Front and 150 other rebels, it said.
Saudi Arabia last Thursday said it would "contribute positively" if the US-led coalition against the Islamic State in Iraq and Syria (ISIS) militants decides on ground action.
Russia, a key ally of the Damascus government, accused Turkey of "preparations for an armed invasion" of Syria, a claim that Ankara dismissed.
Syria's Foreign Minister Walid Muallem warned against any such move, saying: "Any ground intervention on Syrian territory without government authorisation would amount to an aggression that must be resisted."
He added: "Let no one think they can attack Syria or violate its sovereignty because I assure you any aggressor will return to their country in a wooden coffin, whether they be Saudis or Turks."
The head of the elite Revolutionary Guards of Iran, another key Syrian ally, said Saudi Arabia would not dare send in ground forces.
"I don't think they would dare do that... If they do, they will inflict a coup de grace on themselves," Major-General Ali Jafari said.
Turkey last faced such an influx in 2014 when 200,000 people fled the Syrian Kurdish town of Kobane over three days as ISIS and Kurdish fighters battled for its control.
Trucks were seen last Friday carrying tent parts to the refugee camp on the Turkish side, and four more were seen returning to Turkey after delivering food in Syria.
More than 260,000 people have been killed in Syria's conflict and more than half the population has been displaced.
Also last Saturday, the mother of President Bashar al-Assad, Anissa Makhlouf al-Assad, died at the age of 86, state media reported.