Nickelsdorf (Austria) (AFP) - Crowded aboard buses and trains, thousands more migrants flooded into Austria on Sunday as at least 13 desperate refugees drowned making the perilous trip to Europe in search of a better life.
Six children were among those who died off the coast of Turkey after the inflatable dinghy carrying them to Greece collided with a ship, Turkish media reported. Greek reports indicated another two children may still be missing.
As several thousand more migrants arrived in Austria from Hungary via Croatia, Budapest abruptly decided to reopen a border crossing with Serbia whose closure on Tuesday had sparked a surge of migrants into neighbouring Croatia.
The closure of the Horgos-Roszke 1 crossing had added distance and uncertainty for those undertaking the gruelling journey across the Balkans into western Europe, with Croatia saying more than 25,000 had entered its territory since Wednesday.
Within days of the border closure, Croatia said it could not cope with the huge influx and began redirecting migrants back towards Hungary or towards Slovenia, sparking angry reactions from both countries.
Both Zagreb and Budapest have stepped up efforts this week to move the huge crowds through and out of their territory as quickly as possible, with Croatia pushing a record 1,200 migrants onto neighbouring Hungary in the space of an hour on Sunday.
At the Austrian town of Nickelsdorf on the Hungarian border, some 7,000 refugees and migrants arrived on Sunday, a pile-up that caused long waits for onward transport. A snaking line of arrivals were waiting for buses, with others hoping for taxis to take them to Vienna.
"It's known that once you get to Austria, you've arrived," said Saeed, a 23-year-old from Damascus who is hoping his odyssey will end in Germany.
"As we approach the Europe that we want, people are getting nicer and nicer."
- Hungary reinforces its border -
Croatian state-run broadcaster HRT reported a convoy of Hungarian military vehicles arriving at the two countries' border crossing at Beremend, and aired images of officials placing several large metal panels across a road on the Hungarian side.
Workers also arrived with fencing pillars and barbed wire in an apparent effort to reinforce Hungary's border.
The right-wing government in Budapest has already built a razor-wire barrier along much of its border with Croatia, after sealing off its frontier with Serbia in a bid to keep migrants out.
The continent's worst migration crisis since World War II has caused a deep rift between EU members over how to distribute the arrivals.
The massive influx has raised questions over the fate of the Schengen agreement allowing borderless travel across most countries within the 28-nation bloc, with several of them imposing border controls.
There are also bitter divisions over how to distribute the influx fairly between EU members, with several Eastern European countries staunchly opposed to plans for mandatory quotas of refugees.
French President Francois Hollande said Sunday that no EU country should be exempt from taking in people with the right to asylum.
"No one can be exempt or we would no longer belong to the same union built on values and principles," he said.
The United States meanwhile said it would take in 85,000 refugees over the next year, including 10,000 Syrians -- up from 70,000 in the fiscal year ending this month.
- 'We lost the children' -
In Sunday's accident off the Turkish coast, the dinghy that was hit was carrying at least 46 migrants to Lesbos, one of several Greek islands inundated in recent months by tens of thousands of people arriving from Syria, Afghanistan and elsewhere in the Middle East and South Asia.
A survivor whose name was given as Haseen told Greek state news agency ANA: "It was dark, we saw the ship bearing down on us. We tried to signal with flashlights and cellphones but they did not see us."
Thrown overboard, the passengers fought to keep their heads above water. "We lost the children. We could not see them in the dark," Haseen said.
More than 2,800 people have died among the nearly half a million who have braved dangerous trips across the Mediterranean to reach Europe so far this year, according to the International Organization for Migration.
The Italian navy said it carried out two operations off the Libyan coast Sunday, rescuing 146 migrants from a fishing boat in the first incident and another 339 in the second, while the Irish Niamh vessel rescued 125 people from a dinghy.
And the Libyan coastguard said it had rescued 215 migrants from two boats in the Mediterranean.
Many migrants have turned to Turkey's land borders with Greece and Bulgaria to avoid the risky sea crossing.
EU interior ministers are to meet over the crisis on Tuesday, followed by an emergency summit on Wednesday.
The foreign ministers of several eastern European countries -- Hungary, Poland, the Czech Republic, Slovakia, Romania and Latvia -- are also holding talks on the situation Monday with their counterpart from Luxembourg, which currently holds the EU presidency.