Up to 70,000 Syrians are heading for Turkey, threatening to send a new wave of refugees into Europe as Syria's civil war intensifies.
The latest exodus came as Syrian regime forces advanced on the strategically vital opposition stronghold of Aleppo, closing in on a major victory with the help of sustained Russian air strikes on rebel positions.
With about 35,000 new refugees already gathering at Syria's Bab al-Salam crossing with Turkey, European foreign ministers and officials held emergency talks in Amsterdam with their Turkish counterparts to draw up a plan to deal with the crisis.
Jean Asselborn, Luxembourg's Foreign Minister, warned of the "very real prospect that there will be another huge influx of refugees", precipitated by what he called "indiscriminate" Russian bombing around Aleppo.
However, Turkey has resisted EU pressure to open the border-crossing for the refugees.
The Bab al-Salam crossing has remained open until now and has been a key entry point for foreign fighters flocking to join the war.
Suleyman Tapsiz, the Governor of the Kilis border province, said a wave of at least 70,000 refugees was "a possibility" as the noose tightened around Aleppo, where around 350,000 rebels and civilians are trapped.
New arrivals are being accommodated "in eight camps on the Syrian side of the border," Tapsiz said, adding that in Turkey's view there was "no need for now" to transfer them to Turkey which has already absorbed more than two million refugees.
Johannes Hahn, a European commissioner, warned Turkey that it needed to cut dramatically the number of refugees reaching Greece within weeks or the pressure for more border closures and fences will grow.
Frustrated that refugees continue to stream into Greece despite a $5 billion deal between Ankara and Brussels to slow the flows, Hahn said Turkey must show results by the time EU leaders meet this month.
At the border, standing in the pouring rain, 29-year-old Ali begged guards to allow his disabled mother to cross to safety. He said he had lost a seventh member of his family to the bitter war that morning.
Mahmoud, his cousin, died after picking up what he thought was a toy. It was cluster bomb.
Checkpoints and fences are keeping out tens of thousands of refugees fleeing bombardment in northern Syria. The border is ground zero for Syria's refugee crisis.
Many of the 35,000 people camped at the crossing were among the poorest in Syria, having held out through five years of bitter civil war without the funds to escape. Last week, they were left with no choice as forces loyal to Bashar al-Assad cut the rebels' arterial supply line into Aleppo. Yesterday many of northern Syria's remaining rebel-held areas were emptying of civilians. At the crossing point refugees now shelter in scrubland, where night-time temperatures drop below freezing.
The regime assault unfolding on the Syrian side of the border has the potential to change the course of the five-year war, and the men gathered in the border town of Kilis know it. Faces are weary, all eyes trained on the border gates and, beyond.
Taking full control of Aleppo, Syria's largest city before the civil war erupted five years ago, would be a huge strategic prize for Assad's Government. Opposition forces still in east Aleppo have been without power, fuel, water and food for weeks. Aid workers now fear the city could soon fall under a full government siege.
Mevlut Cavusoglu, the Turkish Foreign Minister, said his country would keep its "open border policy" for refugees, but did not indicate when Syrians at the frontier could cross. According to health workers, Turkish control of the border was stricter than ever last week. Even cancer patients, previously subject to a waiver, had been stopped.
Last week, Turkish authorities shot a 12-year-old girl in the head as she crossed over with her family.
Amnesty International called on the authorities to reopen its border, saying Ankara "must not close its doors to people in desperate need of safety".
Russian air strikes,
along with offensives from regime troops and their Iranian and Hizbollah allies have helped tip the balance in favour of an emboldened Assad.
Western donors have pledged £7.5 billion to alleviate Syria's refugee crisis with Britain promising that a million more Syrian children would receive an education in neighbouring countries by the end of next year. Planned reforms are also intended to open up a million jobs for refugees and local people. But the donors' focus on creating better lives for those leaving Syria underscore the fact few believe this war will end any time soon.
Battle may be beginning of the end for Syria's rebels and any hopes for peace
The defeats being suffered by rebel forces across northern Syria and most recently around Aleppo are crushing.
If the rebels are defeated in the country's largest city it could even be the beginning of the end for them, at least as a force able to hold large areas.
The consequences for the Middle East and even Europe would be enormous too: this is the part of Syria that has seen millions flee into Turkey, and then beyond. It is hard to see them returning soon.
But for whom is it a victory? Not, by all accounts, President Bashar al-Assad's forces. Doctors operating in opposition-area hospitals say a large number of "regime" captives being brought in are Afghans, and even Iraqis - members of Shia militias press-ganged into service by Iran, whose generals are directing operations.
Tehran, then, is one winner: Syria is another unstable but strategically significant country into which, like Lebanon, it can insert proxy forces to represent its interests. But it has come at a high price: another Iranian general was killed last week, believed to be the fifth casualty of such rank. Many more Iranian foot soldiers have died, plus thousands of militiamen from Shia communities.
The country that has been most crucial for victory has been Russia. Opposition activists and rebel commanders say, the hundreds of air strikes on rebel positions along the supply routes north of Aleppo were overwhelming. As in Ukraine, President Vladimir Putin's intervention has stopped a decisive geopolitical shift.
As in Ukraine, neither Putin nor anyone else seems to have much idea of what happens next. It seems unlikely that even with Russian and Iranian support Assad can re-establish a peaceful rule over his country. But what it took diplomatically for Russia to achieve this breakthrough means that a peace deal looks impossible.
For weeks, John Kerry, United States Secretary of State, travelled around the region, persuading the opposition to come to Geneva to take part in a Russian-sponsored "peace process".
In doing so, he divided the rebels and forced the "moderates" to take on the local al-Qaeda affiliate, Jabhat al-Nusra, which was excluded from negotiations.
That created a split in the ranks of Ahrar al-Sham, the most powerful Islamist militia in northern Syria - some members sided with Jabhat al-Nusra and some with the "peace party".
The agreement of the rebels to come to Geneva was an apparent triumph for Kerry, securing both talks and persuading rebels to take a stand against al-Qaeda. It was in fact a set-up: the minute the opposition arrived, the Russian bombing of Aleppo started, and the "moderate" opposition, its Western and Gulf backers, and Kerry himself were humiliated.
For those determined to see an end to Assad, the jihadists are now the best option. Those who wish a continuation of his rule have Russia and Iran. For everyone else, there is flight and the ever-less welcoming option of Europe's beaches.
- Additional reporting: Richard Spencer