The van crash happened near the Croatian border with Slovenia after the driver refused to stop at a checkpoint and was chased by a patrol. The driver, presumably a migrant smuggler, managed to get out of the sinking vehicle, fleeing into a nearby minefield. A search for him was ongoing, Croatian police said.
Police pulled the migrants from the sinking van in the Kupa River by breaking its windows, but a woman later died at a hospital.
Last week, Slovenia started erecting 40 kilometers (25 miles) of additional fences on its southern border with Croatia after a considerable increase in the number of migrants trying to illegally cross between the two European Union-member states.
Slovenian police said in July a total of 1,740 migrant crossings were detected, while 7,415 were recorded in the first seven months of this year- about a 50 percent increase compared to the same period last year.
Slovenia has already constructed about 180 kilometers (120 miles) of mostly barbed-wire fence with Croatia since 2015 when the Balkans route saw migrants fleeing wars and poverty in the Middle East, Asia and Africa, crossing the borders in the thousands a day.
Police in North Macedonia said they spotted an abandoned truck Saturday afternoon near the town of Strumica, which borders with Greece, and discovered 30 migrants - 24 Pakistanis, three Iraqis, two Syrians and one Sudan national.
The migrants are believed to have entered illegally from Greece and to have paid smugglers to take them north through Serbia toward Europe's prosperous heartland. Police said they were taken to a camp near the southern town of Gevgelija pending deportation to Greece.
Police said they detained a total of 10,017 migrants who entered the country illegally in the first half of the year.
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