Turkish aid workers have been setting up tents and distributing supplies for thousands of new Syrian refugees kept from entering Turkey at the border, the BBC reports.

Some 35,000 people fled a Syrian government offensive in the Aleppo area last week, trying to enter Turkey’s Kilis border region.

But Turkey has so far closed the border to most of them despite appeals by EU leaders to let them cross.

The country already shelters more than 2.5 million refugees from Syria’s war.

Many Syrians have gone on to seek asylum in the EU and made up the largest group among more than one million refugees and other migrants who entered illegally last year, mainly by sea from Turkey.