Four migrants were found dead near the Slovenian border and two others were taken to hospital in a serious condition after being transported by truck in “inhumane conditions,” Croatian police said on Monday.There was no detail provided on the cause of death, but investigations were underway.Thirteen other people were also found by police near the Croatian village of Donje Prilišće, 70 kilometres southwest of the capital Zagreb, and taken to a detention centre.Police said the group were allegedly dropped at the border by an unknown smuggler who fled.Croatia, a member of the European Union, is a major transit country for irregular migrants seeking to reach Europe via the Balkan route.Earlier this year, a Chinese man died after a migrant boat capsized while crossing a river from Bosnia into Croatia.Last month, 30 people were also rescued from a marsh on the same border.More than 12,500 people used the Balkan route in 2025, according to data from the European border agency, Frontex.Since 2014, more than 400 people have been reported dead or missing while attempting this passage, according to the International Organisation for Migration (IOM).Migrants using this route are often subjected to strict border controls, forcing many to undertake dangerous, irregular journeys across often perilous terrain to evade detection, according to the IOM.The Balkan route was declared officially closed in 2016 when the EU and Turkey struck a deal after thousands used the route to get from Greece through the Balkan countries and on to Western Europe.But despite that announcement, thousands of migrants continue to use it every year.