Hundreds of desperate migrants are trapped behind a razor-wire fence erected by Hungary, as Germany's Angela Merkel calls for an EU summit on the refugee crisis.
While European leaders squabbled over how to manage the continent's biggest migrant influx since World War II, the exodus from war-torn Middle Eastern countries claimed more lives.
Another shipwreck off Turkey killed 22 refugees - among them four children and 11 women - who had tried to reach Europe, where more than half a million people have arrived this year to seek safe haven.
Hungary's conservative Prime Minister Viktor Orban has tried to stop the migrant flow through Balkans countries with the hastily-erected fence along its Serbian border.
He announced plans for a similar barrier on its frontier with Romania.
In addition, Budapest made its first arrests under tough new laws punishing "illegal border-crossing" or damaging the border fence with prison terms of up to three years.
"Why are they doing this?" asked an Afghan woman holding a child on the Serbian side of the fence where some 300 people gathered, some searching in vain for an opening, as Hungarian riot police watched them from the other side.
"It was really bad last night," said Bashir, a 17-year-old Afghan schoolboy who had arrived an hour after the border closed at midnight.
"It was cold, particularly for families with little babies."
The controversial measures are part of Orban's strategy to stem the flow of migrants travelling from Greece and transiting through the western Balkans and Hungary, most of them headed on via Austria to Germany.
But the Hungarian fences sparked fears in Serbia of an unmanageable number of migrants.
Serbia's minister for refugees, Aleksandar Vulin, urged Hungary to reopen its border "at least for women and children".
Hungary's moves have been sharply criticised, with the UNHCR saying it could be in violation of the 1951 Refugee Convention.
Romania, which is a member of the EU but not of the passport-free Schengen zone, criticised the fence planned along its own border as "out of step with the spirit of Europe".
Human rights group Amnesty International said that "meeting those fleeing conflict and persecution with razor wire, troops and draconian new laws, Hungary is showing the ugly face of Europe's shambolic response to the growing refugee crisis".
In Berlin, Merkel and her Austrian counterpart Werner Faymann called for European solidarity to end the chaos and proposed a special EU summit next week.
"Time is running out," Merkel warned, urging an end to the squabbling that has grown more acrimonious since eastern members flatly refused to accept EU-set quotas for taking in refugees.
"We can manage this," Merkel insisted, while defending Berlin's decision last Sunday to reinstate border controls on security grounds, after over 60,000 migrants had arrived in Germany so far this month.
EU officials later announced a meeting of interior ministers for September 22.