European Union officials urged Turkey to let in tens of thousands of Syrian refugees fleeing the fighting in Aleppo, who are stuck at its border with Syria, near Kilis. Around 35,000 Syrians have fled a recent Syrian army offensive again rebel positions, EU foreign policy chief Federica Mogherini said Saturday at a meeting in Amsterdam.

Turkey had a moral and legal duty to help, Mogherini said, adding that EU had given Turkey funding to provide assistance and protection to Syrian refugees. On Thursday, EU approved 3 billion euros ($3.35 billion) in aid to help Turkey cope with the influx of refugees.

On Saturday, Turkey kept its border crossing at Oncupinar closed, even as the number of Syrians at the gateway swelled in the past 48 hours. As many as 70,000 people were expected to head for the border in the coming days, Suleyman Tapsiz, governor of Turkey’s Kilis province told Guardian.

Turkey’s officials are yet to respond to EU’s calls directly but have reportedly maintained that refugees are receiving food and shelter inside Syria, and there was no need to allow them to cross. Approximately 2.5 million Syrian refugees are already living in Turkey.

Aid workers said the refugees were being directed to nearby camps, the Guardian reported.

More than one million refugees, mostly Syrians, have migrated to Europe in the past 12 months. A majority of the migrants crossed into Greece from Turkey before making their way to countries like Germany and Sweden through the Balkans.

Earlier this week, EU reportedly asked Greece to re-establish full control over its border with Turkey in order to preserve the Schengen zone – a bloc of 26 European countries that allow passport-free travel between themselves.

Other European Union officials also called on Turkey to fulfill its international obligations to keep its frontiers open to Syrian refugees Saturday.

"The Geneva convention is still valid which states that you have to take in refugees,” EU Enlargement and Regional Policy Commissioner Johannes Hahn reportedly said Saturday.