India, April 23 -- Sadri Haghshenas spends her days selling borek - a layered, savory pastry - at a shop in Istanbul, but her mind is on her daughter in Tehran.

The family had to send her home to Iran after they ran into difficulties renewing her visa, despite fears that a shaky ceasefire could soon collapse. For years, short-term residency permits have allowed tens of thousands of Iranians to pursue economic opportunities and enjoy relative stability in neighbouring Turkey.

But it's a precarious situation, and the war has raised the stakes. "I swear, I cry every day," Haghshenas said, raising her hands from behind the counter of the pastry shop. "There is no life in my country, there is no life here, what shall I do?"

 A daughter...