Record numbers of people are streaming into EU member Hungary from Serbia, posing a new headache for regional leaders at a summit this week set to be dominated by Europe's worst migrant crisis since World War II.
As criticism mounts over the bloc's failure to find a response to tackle the crisis, Germany said it has stopped returning Syrian asylum-seekers to their first EU port of entry, becoming the first member state to effectively simplify the application process for those fleeing the war-torn nation.
"For the commission, this constitutes a recognition of the fact that we cannot leave the member states at the external borders alone in dealing with a large number of asylum seekers seeking refuge in Europe," said Natasha Bertaud, spokeswoman for the EU Commission.
Under the so-called Dublin rules, the first EU country that an asylum-seeker arrives in is required to process the claimant's application.
In practice, this means that countries on the EU's borders like Greece or Italy are overwhelmed with applications as thousands arrive by sea on their shores.
Hungary, another EU country with external borders, is rushing to build a vast razor-wire barrier to keep out migrants, fearing it will be overwhelmed by asylum requests.
The European Commission on Tuesday said it stood ready to provide Hungary with emergency EU facilities as Budapest struggles to cope with the record numbers arriving.
Almost 2,100 people, the highest ever daily total, crossed into Hungary on Monday near the town of Roszke, one of the few sections of the border not yet sealed off by the barrier.
They were among 7,000 refugees whose hazardous journey to the European Union was temporarily blocked last week when Macedonia declared a state of emergency and shut its borders for three days to halt the huge influx of people mostly fleeing war in Syria.
Authorities reopened the crossing after chaotic scenes involving police lobbing stun grenades at migrants trying to break through the border.
"We were stopped in Macedonia for two days, the riots were terrible, police used guns and tear gas, I saw an old woman beaten, her money and papers taken," said a 29-year-old IT engineer from Mosul in Iraq who said he had left his home to escape the Islamic State group. He asked not to be named.
'Europe's approach not working'
The UN's refugee agency said on Tuesday it expected the number of refugees moving through Macedonia to double to 3,000 a day, many of them women and children.
It warned that the situation was also worsening on the shores of Greece and Italy, where the number of Mediterranean sea crossings was now approaching 300,000 since the start of this year.
Since the beginning of the year, more than 2,370 people have drowned in the Mediterranean, already exceeding the death toll for the whole of 2014, according to the International Organization for Migration.
The UN called on Europe to "establish a human-rights based, coherent and comprehensive migration policy", as the bloc struggles to agree a response to the unprecedented numbers of refugees arriving.
"Let's not pretend that what the EU and its member states are doing is working," said the UN's special rapporteur on the human rights of migrants, Francois Crepeau. He called for "opening up the regular labour markets through smart visas" to be issued to migrants.
His comments came as Britain announced tough new measures against illegal migrant workers, with those caught working without permits in England and Wales facing up to six months in prison.
The migration crisis is set to dominate the summit in Vienna of leaders from the western Balkans region on Thursday that will also be attended by German Chancellor Angela Merkel, whose country expects to take in 800,000 migrants this year, a record number.
The western Balkans has now become one of the main routes into the EU.
More than 1,700 migrants were massed Tuesday in Serbia's Miratovac camp, waiting for an opportunity to cross into Hungary and onward to more prosperous EU countries like Germany or Sweden.
Austria, which lies on the route north, said Tuesday that more than 500 troops would be deployed to help overstretched authorities deal with the large number of migrants arriving from Hungary and Italy in recent weeks.
A key question that the summit would seek to address is why nationals of conflict-free Balkans states make up such a large number of migrants into the EU in the past year.
Nearly half of those arriving in Germany come from countries including Albania and Kosovo.
Some 102,000 migrants arrived in the EU via Macedonia, Serbia, Bosnia and Herzegovina, Albania, Montenegro or Kosovo between January and July this year, versus just 8,000 for the same period in 2014, according to EU border agency Frontex.
Summit host Austria will put forward a five-point plan at the conference including doing more to tackle people-trafficking gangs, a "fairer" distribution of refugees around the EU as well as aid to migrant origin countries.
"There is a pressing need for us to focus on the situation in the western Balkans," Austrian Foreign Minister Sebastian Kurz said earlier.