(VOVworld) - Denmark has tightened controls along its border with Germany, just hours after Sweden imposed similar measures. Danish Prime Minister Lars Loekke Rasmussen said in a press conference on Monday that the temporary controls are to check the flow of travellers coming in from Germany. The measures are not imposed on Danes and Germans.

Checking identity papers on Monday at a train station in Kastrup, Denmark, that serves the main Copenhagen airport. (Photo: Getty Images)

As of midnight Sunday, Sweden demanded that all rail commuters show relevant identification to board trains from Copenhagen Airport to Sweden. Other passengers traveling by buses and ferries also had to go through ID checkpoints before entering the country. Denmark criticized the measure and said Sweden needs to pay for the additional ID checking cost.

Responding to the developments, Germany's foreign ministry said all the moves are against the EU’s principle of free travel and warned that the passport-free Schengen zone was "in danger".