Danish police started to conduct spot checks at some of the country's 15 border crossings with Germany on January 4 and have extended the deadline five times, most recently until May 3.

The checks were originally introduced hours after Sweden began requiring rail, bus and ferry companies to verify the identities of people travelling from Denmark.

Denmark has largely served as a transit country for migrants travelling to Sweden, which before January 4 had some of Europe's most generous asylum rules.

Home Guard to the rescue

Copenhagen has said it plans to deploy 125 members of the Home Guard to help with the spot checks, a measure aimed at easing pressure on police and allowing officers freed up by the move to return to other duties.

Danish Minister for Immigration, Integration and Housing Inger Stojberg said Monday that there was no sign of a build-up of illegal immigrants in the country, but added that the number of asylum seekers in Europe was "historically high."

Danish Minister for Immigration, Integration and Housing, Inger Stojberg

"When asylum seekers without proper ID papers cannot travel to Sweden, there remains a serious risk that many refugees and migrants can become stranded in this country," Stojberg added.

The minister added in a letter to the European Commission that - according to the EU's border agency Frontex - there was still "ongoing pressure on Europe's external borders."

North-bound traffic

Denmark estimates that 630,000 people were subjected to spot checks between January 4 and April 24, with 1,133 being denied entry from Germany and 136 charged with suspected people trafficking.

The country registered almost 3,300 asylum applications between January 4 and April 24 this year after receiving over 21,000 asylum applications in 2015, a 44 percent jump from the 2014 number.

Denmark still receives fewer applications than Sweden, which has 163,000 registered asylum applications.

jbh/jm (dpa, AFP)