In an interview with European newspapers, Tusk said refugees must be subject to tougher screening in order to counter security and terrorism threats.
The former Polish prime minister said EU regulations allow detention for up to 18 months of refugees so that they are checked properly.
"We can and should hold migrants for as long as needed until the verification is complete," Tusk said.
This is while the UN says asylum seekers should only be detained as a last resort.
