BELGRADE, Serbia (AP) — In an abandoned warehouse in the Serbian capital of Belgrade, Rasool, a 12-year-old from Jalalabad, Afghanistan, has spent the last six months sleeping on the ground, warming himself by fires, showering with cold water and eating meals distributed by aid groups.

“This place is so cold and dirty, the smoke from burning fires hurts my eyes and lungs,” he said. “I close my eyes every night and open them in the morning wishing to hear from my elder friends that the border is open and leave to be with my cousins in London.”

He’s among dozens of minors, mostly from Afghanistan and Pakistan, living in the warehouse with hundreds of other, older migrants. Their parents sent them alone to Europe in search of better futures, but they have been stuck in Serbia, unable to cross the heavily guarded borders of neighboring EU nations Croatia and Hungary.

Governments along the so-called Balkan migration route last year closed down their borders as part of efforts to stem a huge influx of migrants. Previously, people arrived by boat or land from Turkey, then could walk or take trains or buses and cross borders freely from eastern Europe to destinations in western Europe.

Since borders closed last March, thousands of migrants have been stranded in Serbia, waiting for them to reopen or trying to scrape together enough money to pay smugglers to take them.

Rasool says his mother and father supported his efforts to leave Afghanistan because the Taliban made it unsafe and he wanted to study and have a peaceful life.

“I miss my parents so much,” he said.

Liaqat, a 12-year-old from Khogyani, Afghanistan, said he left nine months ago, traveling to Pakistan and then on through Iran, Turkey and Bulgaria before arriving in Serbia. He and three new friends do everything together, and he’s learned how to cook.