CROATIA: After suddenly finding itself in the path of Europe's biggest tide of migrants for decades, Croatia said on Friday it could no longer offer them refuge and would wave them on, challenging the EU to find a policy to receive them. The migrants, mostly from poor or war-torn countries in the Middle East, Africa and Asia, have streamed into Croatia since Wednesday, after Hungary blocked what had been the main route with a metal fence and riot police at its border with Serbia. 'We cannot register and accommodate these people any longer,' Croatian Prime Minister Zoran Milanovic told a news conference in the capital Zagreb. 'They will get food, water and medical help, and then they can move on. The European Union must know that Croatia will not become a migrant 'hotspot'. We have hearts, but we also have heads.' The arrival of 17,000 since Wednesday morning, many crossing fields and some dodging police, has proved too much for one of the EU's less prosperous states in a crisis that has divided the 28-nation bloc and left it scrambling to respond. A record 473,887 refugees and migrants have crossed the Mediterranean to Europe so far this year, the International Organization for Migration said, most of them from countries at war such as Syria who are seeking a better, safer life. Hundreds of thousands have been trekking across the Balkan peninsula to reach the richer European countries to the north and west, especially Germany, which is preparing to accept 800,000 migrants this year. But that has wrongfooted the European Union, which has come up with no common policy to deal with the biggest wave of migration to Western Europe since World War Two. Hungary acted on its own to shut the main route this week by closing its border with Serbia, leaving thousands of migrants scattered across the Balkans searching for alternative paths. Croatia, offering an overland route to Germany bypassing Hungary, found itself suddenly overwhelmed, and began sending migrants in trains and buses to Hungary. Gyorgy Bakondi, head of Hungary's national disaster unit, said more than 4,000 migrants had arrived from Croatia on Friday without any prior consultation, and up to 1,200 more could come before the end of the day. With tempers clearly fraying, he said authorities had seized a Croatian train carrying migrants to the town of Magyarboly, disarmed the police who were escorting it and arrested the driver. Hungarian government spokesman Zoltan Kovacs said the incident 'raised the suspicion of a border violation'. However, Croatian police spokeswoman Jelena Bikic said no one had been disarmed or arrested, the escort had been agreed in advance, and the police had returned to Croatia. Hungary did, however, agree earlier in the day to register at least 1,000 migrants delivered from Croatia. 'TIME TO DEAL DIFFERENTLY' While Zagreb made welcoming statements earlier this week, Milanovic said he had called a session of Croatia's National Security Council and that it was time to deal with the problem differently. The president has told the military to be ready if called on to help stop the flow of people. European Commission President Jean-Claude Juncker spoke to Milanovic by phone to offer Croatia technical and logistical help in coping with the flood of migrants. Croatia, the EU's newest member state, has already closed almost all roads from the border. Interior Minister Ranko Ostojic said if the crisis continued 'it is a matter of time' before the border was shut completely, though Milanovic, in his remarks, questioned whether even that would keep migrants out. Police have rounded up many migrants at the Tovarnik railway station on the Croatian side of the border with Serbia, where several thousand spent the night under open skies. 'We are so exhausted,' said Hikmat, a bare-footed 32-year-old Syrian woman from Damascus, after a journey, like many others, by sea and then through the Balkans to the border between the two former Yugoslav republics. She said she had been travelling for two months with her son, and added: 'Look at me. I just want to get anywhere where we will be safe.'