into the surrounding corn fields.
"I just want to cross the border," said a young Syrian student wearing a black Iron Maiden t-shirt, a sad smile on his face.
Standing just metres from the shallow river which marks the border between Slovenia and Croatia, he told AFP he tried to slip across but was stopped by Slovenian police.
"They closed the border for us, maybe forever."
As the chaos spread, the UN´s refugee agency (UNHCR) and the International Committee of the Red Cross issued separate pleas for the 28-member bloc to agree on a common policy for handling the situation and minimising the human misery.
"The countries affected must work together closely instead of closing their borders like they are doing at the moment," ICRC President Peter Maurer told German weekly Der Spiegel.
And UNHCR spokesman Adrian Edwards warned that time was running out, saying recent events in Hungary and elsewhere "demonstrated the chaos and confusion being caused by the absence of a coherent and united response to Europe´s refugee situation."
Two key EU meetings due to take place next week are "crucially important" for reaching some form of agreement, he said.
"These occasions may be the last opportunity for a positive, united and coherent European response to this crisis. Time is running out."
On the ground in eastern Croatia, thousands spent the night camping rough with little food or shelter around Tovarnik, just across the border from Serbia, and by Friday morning were waiting in vain for transportation westwards.
"More and more people are coming from Serbia. I´ve just seen 60 Syrians that just arrived and one young man said there were 1,000 more behind them," said UNHCR spokesman Babar Baloch as the Red Cross treated exhausted and dehydrated travellers.
"I don´t think the authorities were expecting 10,000 in two days," he said.
"They were ready for some, but this has gone beyond their expectations."
Official figures released on Friday showed the EU received 213,000 asylum applications between April and June, up 85 percent from the same period in 2014, with over one third filed by people Syria or Afghanistan.
Germany had the highest number, with more than a third of the total, while Hungary was the country that received the most asylum applications relative to its population size, the Eurostat agency said.
As Germany has opened its gates, Hungary has done the opposite, sparking a wave of anger as it sealed off its southern border with Serbia and announcing plans for a similar fence along its frontier with Romania.
And on Friday, its hawkish premier Viktor Orban said hundreds of troops had begun work on a 41-km section of the 330-kilometre border along its frontier with Croatia to keep migrants out.
"There will be no sandhill or molehill to hide behind, we will defend our borders," he told Hungarian public radio.
Earlier this week, Hungarian riot police fired tear gas and water cannon at refugees on its southern border, prompting UN rights chief Zeid Ra´ad Al Hussein to suggest that Budapest´s policies vis-a-vis migrants were apparently guided by "xenophobic and anti-Muslim views."