The day European borders came back

A surprise move by Germany on Sunday (13 September) to reintroduce border controls to deal with the influx of migrants has set in motion a domino effect in the passport-free Schengen zone, with Austria deciding to do the same, while the Czech Republic and Slovakia reinforced their frontiers on Monday.

Heading into talks with her counterparts in Brussels on Tuesday, Austrian Interior Minister Johanna Mikl-Leitner said Vienna would "proceed as Germany did... and we will conduct these temporary border controls."

The Austrian army sent 2,200 soldiers to the border area to "help police tackling the refugee crisis", according the ministry's statement.

Slovakia and the Czech Republic have also reinforced their borders, with Slovakia sending an additional 220 officers to the border.

The Czechs have taken the step of beefing up the staff patrolling the border with Austria, but said they will not reintroduce border controls.

Hungary has also sealed its frontier with Serbia, an external Schengen border.

Poland's prime minister, Ewa Kopacz i, said Monday that Poland is ready to impose border controls with other EU members in case of threats to border security.

Germany's decision "could detour migrants that could put pressure on the Netherlands," said Dutch minister for immigration Klaas Dijkhoff i upon arriving in Brussels. He added that the Netherlands would not reintroduce border controls, but would step up border patrols.

Under EU law, in the case of "unforeseeable" circumstances, member states can reintroduce border controls within the Schengen zone for 10 days, with a possibility of extending it up to 2 months.

"The objective of our efforts must be to help ensure that we can go back to the normal situation of open borders between Schengen members as soon as [is] feasible", a European Commission spokesman said on Monday.

According to the European Commission, this is only the second time border controls were reinstated due to unforeseen events. Since 2013 Schengen has only been suspended 6 times.

Berlin's decision to reintroduce border controls already put pressure on EU member states whose home affairs ministers are meeting in Brussels to come to a political agreement on the EU commission's proposal to relocate 120,000 migrants on a mandatory basis across Europe.

Last-minute rush

There is a clear rush on the Hungarian-Serbian border, which was closed down on Monday afternoon, with police blocking the main migrant crossing point. On Tuesday, harsher punishments will come into force in Hungary for crossing, or damaging, the border fence, which can result in 3 years in prison.

The Hungarian government also has the possibility under the new laws to introduce a "state of crisis due to mass migration". Over the weekend 4,300 army personnel helped out police with border control.

Hungarian police said that by noon on Monday 5,353 migrants had crossed into Hungary, and Sunday saw a record 5,809 people. In total, 191,702 migrants have crossed into Hungary this year.

The UN said that Hungary had effectively stopped registering migrants crossing from Serbia and was transporting them straight to the Austrian border by train.

According to media reports, Serbian authorities are attempting to "push through" as many as 30,000 migrants to Hungary.

The United Nations refugee agency warned that confusion surrounding border policies around Europe could leave migrants, many of whom risked their lives to make the journey, in "legal limbo".