Germany has said the passport-free Schengen zone is “in danger” after both Denmark and Sweden introduced border controls to stem the flow of migrants.

Responding to the new border controls in the Nordic countries, German foreign ministry spokesman Martin Schaefer told reporters: "Freedom of movement is an important principle - one of the biggest achievements [in the European Union] in recent years….Schengen is very important but it is in danger.”

The concerns raised over the passport-free zone came as Denmark announced it would introduce controls at its border with Germany just hours after neighbouring Sweden introduced similar measures.

We’ll tell you what’s true. You can form your own view. From 15p €0.18 $0.18 $0.27 a day, more exclusives, analysis and extras.

Danish prime minister Lars Løkke Rasmussen told reporters in Copenhagen that police were conducting spot checks on travellers crossing the border from Germany. Hours earlier Sweden imposed border controls on the Oresund bridge – which connects Malmo in southern Sweden and Copenhagen in Demark – making it harder for bother migrants and commuters to travel.

Mr Rasmussen, referring to the Swedish measure, said: “When other Nordic countries seal their borders it can have major consequences for Denmark… It can lead to more asylum seekers.” The Danish prime minister insisted, however, there would be no issues for “ordinary” Danes and Germans who wished to cross the border.

Shape Created with Sketch. Refugees march from Hungary to Austria Show all 10 left Created with Sketch. right Created with Sketch. Shape Created with Sketch. Refugees march from Hungary to Austria 1/10 Refugees march from Hungary to Austria Migrants walk in a long line along the highway near Budapest, Hungary, Friday, Sept. 4, 2015 AP 2/10 Refugees march from Hungary to Austria Migrants walk on the railway tracks between Bicske and Szar, some 40 km west of Budapest, Hungary, 04 September 2015 EPA 3/10 Refugees march from Hungary to Austria The destination for most of those walking is reportedly Austria AP 4/10 Refugees march from Hungary to Austria Most refugees have come to Hungary through the southern border with Serbia AP 5/10 Refugees march from Hungary to Austria People walk in a long line along the highway near Budapest, Hungary AP 6/10 Refugees march from Hungary to Austria Over 150,000 people seeking to enter Europe have reached Hungary this year AP 7/10 Refugees march from Hungary to Austria Refugees walk along Budaorsi Street on their way out of Budapest EPA 8/10 Refugees march from Hungary to Austria Refugees hold up an EU flag as they on the highway out of Budpest AP 9/10 Refugees march from Hungary to Austria Refugees exit Budapest AP 10/10 Refugees march from Hungary to Austria Hundreds of migrants walk after leaving the transit zone of the Budapest main train station AFP 1/10 Refugees march from Hungary to Austria Migrants walk in a long line along the highway near Budapest, Hungary, Friday, Sept. 4, 2015 AP 2/10 Refugees march from Hungary to Austria Migrants walk on the railway tracks between Bicske and Szar, some 40 km west of Budapest, Hungary, 04 September 2015 EPA 3/10 Refugees march from Hungary to Austria The destination for most of those walking is reportedly Austria AP 4/10 Refugees march from Hungary to Austria Most refugees have come to Hungary through the southern border with Serbia AP 5/10 Refugees march from Hungary to Austria People walk in a long line along the highway near Budapest, Hungary AP 6/10 Refugees march from Hungary to Austria Over 150,000 people seeking to enter Europe have reached Hungary this year AP 7/10 Refugees march from Hungary to Austria Refugees walk along Budaorsi Street on their way out of Budapest EPA 8/10 Refugees march from Hungary to Austria Refugees hold up an EU flag as they on the highway out of Budpest AP 9/10 Refugees march from Hungary to Austria Refugees exit Budapest AP 10/10 Refugees march from Hungary to Austria Hundreds of migrants walk after leaving the transit zone of the Budapest main train station AFP

He added: "If the European Union cannot protect the external border you will see more and more countries forced to introduce temporary border controls," the prime minister said.

The Swedish government decided to tighten border controls after 160,000 people applied for asylum in Sweden last year — the highest number in Europe except for Germany. Most of them were from Syria, Iraq and Afghanistan.

Additional reporting by Press Association

We’ll tell you what’s true. You can form your own view.

At The Independent, no one tells us what to write. That’s why, in an era of political lies and Brexit bias, more readers are turning to an independent source. Subscribe from just 15p a day for extra exclusives, events and ebooks – all with no ads.

Subscribe now