Just hours after Swedish rules went into effect requiring train passengers traveling from Denmark to show ID, the Danish government announced it had beefed up border controls with Germany as of yesterday.

"We are introducing temporary border controls, but in a balanced way," Danish Prime Minister Lars Loekke Rasmussen told reporters in Copenhagen, adding there would be no problem for "ordinary" Danes and Germans to cross the border.

The moves were the latest by European Union countries to suspend an agreement to keep internal borders open after 1 million migrants entered the 28-nation bloc in 2015, most of them by crossing the Mediterranean to Greece or Italy.

"If the European Union cannot protect the external border, you will see more and more countries forced to introduce temporary border controls," Loekke Rasmussen said. He said the Danish move was in response to new ID checks introduced by Sweden yesterday for all passengers entering the country by train, bus or ferry.