sentences:  On September 15, 2015, Hungary announced it would start arresting people crossing the border illegally, and as of early 16 September, Hungary had detained 519 people and pressed criminal charges against 46 for trespassing.Thousands of migrants were subsequently led to pursue alternative routes through Croatia from Serbia.After Hungary closed its border with Serbia on September 15, migrants headed towards the Serbian town of Šid, less than 10 kilometers from the Croatian border.