ATHENS/IDOMENI: Greece moved to slow the flow of migrants from its islands to the mainland on Friday as hundreds of refugees left reception centers with nowhere to go as countries in the Balkans progressively shut down their borders.

From its northern frontier with Macedonia to its port of Pireaus in the south, Greece was inundated with refugees and migrants after border shutdowns through the Balkans route to central and northern Europe trapped thousands.

At Idomeni, a small community on the border with Macedonia, Reuters witnesses saw hundreds of families walking toward the frontier to join an estimated 3,000 more at a makeshift camp where many pitched tents in a field close to razor wire fence.

More than 500 km further south, hundreds of people were temporarily accommodated at a disused airport west of Athens. Sleeping mats were strewn across the terminal among biscuit wrappers as many women sat on the floor, some weeping.

“Planes bombed our homes, it was dangerous to stay there,” said mother of three Rajiya Zara, 38, nine months pregnant. “I’m afraid for my children.”

Between 300 and 400 people refused to stay at the airport, and took off on their own. “Help Us,” a large piece of paper held by one said. “We are human, open the borders,” read another, scrawled on a sleeping mat.

Greece asked its passenger ferry companies and travel agencies on Friday to cut back on bringing migrants and refugees from front-line islands to the mainland and said its own chartered ships would stay put for a few days.

The moves, described by Greece’s shipping minister as temporary, are designed to stem a flow of people mostly fleeing from violence in the Middle East.

Most refugees arrive in the European Union after a short but at times dangerous journey by small boats from Turkey to nearby Greece islands such as Lesbos.

The German authorities said in a parliamentary document on Friday it does not know the whereabouts of 130,000 asylum seekers.

Out of some 1.1 million asylum seekers registered in 2015, "about 13 percent did not turn up at the reception centers to which they had been directed," the government said in a written reply to a question from a lawmaker of the Left Party.

Some may have returned to their home countries, traveled on to another country, or gone underground, it said, adding that there may also have been repeated registrations of the same individual.

In Budapest, Hungary's justice minister accused the EU on Friday of overstepping its mandate by seeking to impose migrant resettlement quotas on member states and said Budapest could hold its planned referendum on the issue in 150 days at the earliest.