Six European countries have so far reimposed random border checks to counter secondary migration within the bloc.
Secondary migration is the movement of non-EU migrants — including refugees and asylum seekers — who illegally move from the member state they first arrived in.
According to Eurodac — an EU fingerprint database for identifying asylum seekers and irregular border-crossers — 99,032 hits related to data for persons apprehended while irregularly crossing the external border of a member state who have subsequently lodged an application for international protection in another member state were registered in 2017.
A further 129,433 hits were recorded related to data for persons found illegally staying in a member state despite having previously lodged an application for international protection in another member state.
The European Council urged member states last year to "take all necessary internal legislative and administrative measures" to counter secondary movements of asylum seekers.
It argued that such movements "risk jeopardising the integrity of the Common European Asylum System and the Schengen acquis" and flagged that there is no "EU-wide clear picture" on the scale of secondary migration.
As per the Dublin regulation, asylum seekers who do not have close family members in another EU country or were not previously issued a residence permit from another member state must make their asylum application in the country they first arrived in and stay there until their claim has been processed.
Among the 26 member states of the Schengen area, border controls had largely been abolished but six countries — Austria, Denmark, France, Germany, Norway and Sweden — started introducing temporary checks as the migrant crisis unfolded.
Germany had until now only ordered checks along its borders with Austria — a measure it extended again just last week until spring 2020.
But on Sunday, Interior Minister Horst Seehofer announced that police would intensify checks along the country's entire 3,700 km border.
"Security starts at the border," Seehofer wrote in a statement released on Twitter.
"I have ordered the Federal Police to intensify stop and search (operations) on all German internal borders," he added.
A spokesman for the Federal Interior Ministry told the DPA news agency that there is "still a high number of illegal border crossings."
Irene Mihalic, the Green party's spokesperson for home affairs, criticised the latest decision, saying it "harms the European spirit."