The European Union's migration chief rebuked Hungary on Thursday for its tough handling of a flood of refugees as asylum seekers thwarted by a new Hungarian border fence and repelled by riot police poured into Croatia, spreading the strain.
Croatian police said more than 5,000 migrants had arrived from Serbia since Hungary sealed its southern EU border with Serbia on Tuesday. Hungarian security forces fired tear gas and water cannon to disperse rock-throwing refugees on Wednesday.
"Maybe the border to Croatia is open, maybe it is closed, but we are going to try," said a Syrian man at the Serbian border town of Sid who gave his name as Abed, one of the many who had given up hope of crossing from Serbia into Hungary.
Several thousand migrants gathered at the Tovarnik railway station on EU-member Croatia's side of the border with Serbia, sitting or lying by the tracks trying to shade themselves from the sun.
"I just want to go," said Syrian Kamal Al'hak. "I may return to Syria, but only in a few years. It's too dangerous there now."
The head of Germany's Office for Migration and Refugees resigned for personal reasons after being criticised for being slow in processing applications from a record number of asylum seeks. German police said the number of refugees arriving in Germany more than doubled on Wednesday to 7,266.
Deep differences over how to cope with the influx of people mostly fleeing war and poverty in Syria, Iraq, Afghanistan and Pakistan have triggered a chain of beggar-thy-neighbour actions among European countries, sparking a crisis in the 28-nation EU.
EU commissioner for migration Dimitris Avromopoulos told a joint news conference with Hungary's foreign and interior ministers that most of those arriving in Europe were Syrians "in need of our help".
"There is no wall you would not climb, no sea you would not cross if you are fleeing violence and terror," he declared, saying barriers of the kind Hungary has erected were temporary solutions that only diverted refugees and migrants, increasing tensions.
Hungarian Foreign Minister Peter Szijjarto hit back at criticism from U.N. and European officials and human rights groups, saying that siding with rioting migrants, who pelted Hungarian police with rocks in clashes that injured 20 police, was encouraging violence.
"It is bizarre and shocking how some members of international political life and the international press interpreted yesterday's events," he said. "All these people will be responsible if these events are repeated today, tomorrow or the day after tomorrow."
Muslims 'will outnumber us'
Hungarian Prime Minister Victor Orban, who has blamed Germany for stoking the wave of migrants entering his country after Chancellor Angela Merkel rolled out the welcome mat for Syrian refugees, said Muslims would end up outnumbering Christians in Europe if the policy continued.
"I am speaking about God. I am speaking about culture and the everyday principles of life, such as sexual habits, freedom of expression, equality between men and woman and all those kind of values which I call Christianity. If we let the Muslims into the continent to compete with us, they will outnumber us. It's mathematics. And we don't like it," Orban said in an interview published in several European newspapers including The Times.
Neighboring Slovakia has also invoked religious differences as a reason for rejecting mandatary quotas to share out refugees among EU nations, as the European Commission has proposed. The EU executive says the right to asylum is indivisible and cannot be linked to religious or ethnic considerations.
EU interior ministers are due to hold another special meeting next Tuesday to try to overcome differences on handling the migration crisis, which has prompted several EU countries led by Germany to reintroduce temporary border controls.
The European Parliament endorsed on Thursday a Commission proposal for the mandatory relocation of 120,000 migrants from Italy, Greece and Hungary, opposed by four central European states including Hungary itself.
Merkel has called for an emergency EU summit on the issue and two German ministers have spoken of cutting European funds to central European member states that refuse to take their allotted share of refugees.
The future of border-free travel in the EU's Schengen zone of 26 continental European states has been cast in doubt by the uncoordinated national actions to revive frontier checks.
Croatia, Slovenia next
Croatia, the most recent country to join the EU but not yet the Schengen area, said it would not halt the influx. That puts tiny Slovenia next in line to receive the thousands of migrants, trying to reach Austria then Germany and other more prosperous countries of northern and western Europe.
"We are tired. We are exhausted. We have been travelling for 10 days. We just want to pass to through Croatia and go to Germany," said 19-year-old Salim from Syria who crossed at Sid.
Slovenian Prime Minister Miro Cerar said his country would stick to the Schengen rules, which require it to register and fingerprint migrants and asylum seekers on arrival. Many refugees have refused to be registered and destroyed their identity papers in their quest to reach Germany.
Hundreds more migrants left Serbia's northern border with Hungary by bus bound for Croatia, emptying makeshift camps created after Hungary sealed the frontier, a Reuters reporter in the Serbian village of Horgos said.
Bulgaria said it was sending more soldiers to strengthen controls along its border with Turkey and avoid a refugee influx. About 600 migrants tried to cross the border in the last 25 hours but returned voluntarily after seeing it was well guarded, a Bulgarian Interior Ministry official said.
Bulgaria is a member of the EU but not of the Schengen area.