"One thing is clear, the pressure of migration will not abate in the coming years. Migration is a problem that can bring down governments," Schallenberg said in an interview with German newspaper Bild am Sonntag.
Germany should also discuss measures to combat illegal migration, Schallenberg said, adding that the deportation issue is an "Achilles' heel" of the European Union's asylum system.
To deal with the problem, European countries should put much more pressure on migrants' countries of origin and use the European Union’s influence, Schallenberg said.
"This means that we must question EU customs preferences or visa facilitation and adjust development aid for countries that do not cooperate with us on repatriation. But that's not all. First, we need a proper defense of our external borders," Schallenberg said.
A report by the European Union Agency for Asylum released in October showed that over 800,000 asylum applications have been filed in EU countries, Switzerland, and Norway since the beginning of this year, meaning that the total number of applications is likely to exceed 1 million by the end of the year for the first time since 2016.