SID, Serbia (Reuters) - Mudassir, 18, from Pakistan s city of Peshawar has tried to enter the European Union 30 times but was always caught and sent back to his starting point in Serbia.  Now, he and dozens of other migrants are braving near-freezing temperatures in shrubs and fields near Sid, a northwestern Serbian town just outside European Union s member Croatia, hoping to make another border run.  They spend nights in tents and makeshift shelters in a shrub they call - the jungle.   I have tried 30 times, I am in Serbia for 16 months, ... I am tired of sleeping in the  jungle ,  said Mudassir, dressed in a black hooded jacket. Meanwhile, other migrants, all young males, huddled outside an abandoned printing factory in the outskirts of Sid, waiting for a meal delivered by an international volunteer group, the No Name Kitchen.  The so-called Balkan route for migrants was shut last year when Turkey agreed to stop the flow in return for EU aid and a promise of visa-free travel for its own citizens. But people mainly from the Middle East, Africa and Asia continued to arrive in Serbia, mainly from Turkey, via neighboring Bulgaria, attempting to enter Croatia and the EU. According to official data there are as many as 4,500 migrants in government-operated camps in Serbia. Rights activists say that hundreds are scattered in the capital Belgrade and towns along the Croatian border.  Muhammad, 22 from the Moroccan town of Oujda, said he has tried to reach the EU 26 times. Three times he made it to Slovenia, but was caught and deported back to Serbia.  I will try again ... my family is in France and my girlfriend is in Italy,  Muhammad said. Bruno Alvares of the No Name Kitchen said migrants are given two meals a day, water, clothes, footwear and tents.   Even if it is cold, it doesn t matter, they will keep on trying because there s ... no evolution in their lives in camps,  Alvares said.  Migrants who cannot afford to pay smugglers, often hide in passing trucks and freight trains or ride on the top of them. Recently an Afghan girl was killed by a train as she and her family attempted to cross into Croatia. 