German Chancellor Angela Merkel is renewing a pledge to make a "national effort" to ensure that failed asylum-seekers return home, while stressing the need to show their home countries "respect."

Speeding up deportations and voluntary returns of people whose asylum claims are rejected has gained new urgency following the Dec. 19 truck attack on a Christmas market in Berlin. Investigators say the truck was driven by a rejected Tunisian asylum-seeker whom Germany hadn't managed to deport because Tunisia initially refused to recognize him as its citizen.

Merkel told a conference of civil servants on Monday that "we will work on a national effort to return" people to their homelands. She added: "This will only succeed if we negotiate with respect with the countries to which they have to be returned."