EDIRNE, Turkey - At least 22 Greece-bound migrants drowned on Tuesday when their boat sank off Turkey, officials said, as police blocked hundreds of others seeking to find an alternative route to Europe by land.

Eleven women and four children were among the victims of the latest migrant shipwreck in the Aegean Sea, where three-year-old Syrian boy Aylan Kurdi drowned two weeks ago, the Dogan news agency said.

A further 249 passengers were rescued from the wooden boat which set off from the southwestern Turkish resort town of Datca for the nearby Greek island of Kos, the Turkish coast guard said. The migrants’ nationalities was not yet known.

The deaths brings to 24 the amount of refugees to have drowned off Turkey in the last day after two Syrians drowned trying to cross to the Greek island of Samos, Dogan reported.

The route across the Aegean Sea from Turkey to Greece has become the busiest for migrants and refugees fleeing conflicts and misery in Syria, Iraq and other Middle Eastern and Asian countries to Europe.

Of the more than 430,000 migrants and refugees to have reached Europe via the Mediterranean this year, some 300,000 landed in Greece, the International Organization for Migration (IOM) said Friday.

Faced with the mounting death toll at sea, a number of refugees wanting to leave Turkey have opted instead to take buses to Greece - but on Tuesday found themselves thwarted by Turkish authorities.

Around 1,000 migrants who had gathered in the western city of Edirne, close to the Greek border, were being barred by military police from leaving the bus station, an AFP photographer reported.

Meanwhile, Serbia urged Hungary on Tuesday to reopen its razor-wire border fence erected to stop a record wave of migrants, as Germany’s Angela Merkel called for an EU summit on the refugee crisis. While European leaders squabbled over how to manage Europe’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 via Balkans countries with the hastily-erected fence along its Serbian border, completed Tuesday, and 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,” he told AFP.

The controversial measures are part of Orban’s strategy to stem the flow of migrants - more than 200,000 of whom have entered his country so far this year - 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.

The Balkan state’s minister for refugees, Aleksandar Vulin, urged Hungary to reopen its border, “at least for women and children,” speaking to AFP at the Horgos crossing, where around a hundred people were waiting for the frontier to reopen.

The foreign minister of EU-hopeful Serbia, Ivica Dacic, said that “the idea of returning all migrants to Serbia, with others flowing in from Greece and Macedonia, is unacceptable, because we would then become the centre of arrivals”.

“We would like to be part of the solution to the problem, but this can’t be to our detriment,” Dacic said, adding that “Serbia cannot handle this”.

Hungary’s moves have been sharply criticised, with the UN refugee agency 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 charged 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,” she 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.

Faymann warned of a “humanitarian catastrophe” if Europe fails to take a united stance on the crisis, saying “no one who is in search of protection should lose their lives”.

EU officials later announced a meeting of interior ministers for September 22.

Berlin’s move to bring back border controls has sparked a domino effect, with Austria and Slovakia also reimposing identity checks in a further blow to Europe’s vaunted passport-free Schengen zone.

The European Commission said it was informed Austria would temporarily reintroduce controls at midnight (2200 GMT Tuesday) with Hungary, Italy, Slovakia and Slovenia.

With Poland and the Netherlands also considering similar measures, there are fears the Schengen system could collapse, even though its rules do allow states to impose temporary controls for security reasons.

Germany’s new border checks caused long traffic jams on the frontier with Austria. Since Sunday the pace of new arrivals has slowed with some 2,000 people crossing, police said.

New figures from the EU’s Frontex border agency meanwhile showed more than half a million people had arrived in the year to August 31 - almost double last year’s total.

“If we could work and live in safety we wouldn’t be here,” said one Afghan teenager waiting in vain to cross into Hungary.

“How are we supposed to live with no future? If I die I want it to be for something, for something good, for my rights.”