BERLIN -- German Chancellor Angela Merkel said Friday that Germany wanted to increase deportation of failed asylum seekers to ensure better safety in the country.

The chancellor made the remarks in a statement issued after the confirmation that Anis Amri, a Tunisian national suspected of carrying out a truck attack on a Christmas market in downtown Berlin, was shot and killed by Italian police officers in a routine patrol in Milan early Friday morning.

Merkel mentioned specifically asylum seekers from Tunisia, saying that she had told Tunisian President Beji Caid Essebsi in a phone conversation that Germany wanted quicker deportation of Tunisian asylum seekers whose applications had been rejected.

"I told the Tunisian president that we have to significantly speed up the deportation process and increased the number of people expelled," the chancellor was quoted as saying in the statement.

The truck attack on the Christmas market raised many questions, she said, vowing that her government would take necessary measures to make the country better secured.

She said she had ordered a comprehensive investigation into the attack which took place near Berlin's iconic Kaiser Wilhelm Memorial Church on Monday evening, killing 12 people and injuring 48 others.