REUTERS - Aid trucks and ambulances entered Syria from Turkey on Sunday to deliver food and supplies to tens of thousands of people fleeing an escalating government assault on Aleppo, as air strikes targeted villages on the road north to the Turkish border.
Russian and Syrian forces intensified their campaign on rebel-held areas around Aleppo that are still home to around 350,000 people and aid workers have said the city - Syria's largest before the war - could soon fall.
The Syrian Observatory for Human Rights, which monitors the war, said air strikes, thought to be from Russian planes, hit around the villages of Bashkoy, Haritan and Kfr Hamra north of Aleppo on Sunday, the latter two lying near the road to Turkey.
Russia's intervention has tipped the balance of the war in favor of President Bashar Assad, reversing gains the rebels made last year. Advances by the Syrian army and allied militias, including Iranian fighters, are threatening to cut off rebel-held zones of Aleppo.
"In some parts of Aleppo the Assad regime has cut the north- south corridor ... Turkey is under threat," Turkish President Tayyip Erdogan was quoted by the Hurriyet newspaper as telling reporters on his plane back from a visit to Latin America.
Turkey's armed forces had the full authority to counter any threats to its national security, he said, although senior government officials have said the NATO member does not intend to mount any unilateral incursion into Syria.
Sunni Arab powers in the region, which, like Turkey, want to see Assad removed from power, have expressed readiness to intervene with ground forces provided it is part of a coordinated international effort.
The United Arab Emirates (UAE) said on Sunday it was ready to send ground troops to Syria as part of an international coalition to fight against Islamic State militants.
Saudi Arabia said last week it was ready to participate in any ground operations in Syria if the U.S.-led coalition decided to start such operations.
Syria would resist any ground incursion into its territory and send the aggressors home "in coffins", its foreign minister said on Saturday, comments clearly aimed at the UAE and Saudi Arabia.
Taking full control of Aleppo would be a huge strategic prize for Assad's government in a five-year conflict that has killed at least 250,000 people across the country and driven 11 million from their homes. It could also push a massive new wave of refugees to the Turkish border.
Turkish border under pressure
Turkey has kept an open-door policy to civilians fleeing Syria throughout the conflict but is coming under growing pressure from Europe to stem the flow of migrants, and from the United States to secure the border more tightly.
It is already sheltering more than 2.5 million Syrians, the world's largest refugee population. But at the Oncupinar crossing, which has been largely shut for nearly a year, the newest arrivals were being shepherded into camps on the Syrian side.
"If those (refugees) have come to our door and they have no other choice and if needed we will let those brothers in, we have to do that," Erdogan was quoted as saying.
Aid officials at the Oncupinar border crossing said their efforts for now were focused on getting aid to the Syrian side of the border, where Turkish agencies have set up new shelters.
"We're extending our efforts inside Syria to supply shelter, food and medical assistance to people. We are already setting up another camp," an official from the Turkish Humanitarian Relief Foundation (IHH), which is funded by donations and carries out humanitarian work inside Turkey and abroad, told Reuters.
"At the moment all our preparations are to make sure these people are comfortable on the Syrian side of the border."
At a camp at Bab al Salama, inside Syria and across from Oncupinar, children played in the muddy lanes between rows of tents lashed by rain. Some were ripped and caked with mud, but others appeared to be newly set up.
A flag of the opposition Free Syrian Army fluttered over the road leading out towards the Syrian city of Azaz along which many of the displaced have travelled in recent days. Opposition fighters armed with Kalashnikovs wandered nearby.
As many as 55,000 people are fleeing towards Turkey, Foreign Minister Mevlut Cavusoglu told reporters on Saturday as he left a meeting with EU foreign ministers in Amsterdam. Turkey's "open border" policy would be maintained, he said.
But Turkey is struggling to stop the flow of migrants trying to make perilous onward journeys into Europe.
Two female migrants, one aged 14 or 15, died of cold after crossing the Turkish-Bulgarian border late on Saturday in a mountainous area thick with snow, Bulgaria's interior ministry said. Their nationalities could not immediately be confirmed.
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