Germany's top migration official says he will immediately ban a local branch office of Germany's Federal Office for Migration from making any further asylum decisions.

The unprecedented decision comes amid a scandal over the improper granting of asylum requests which also has put the head of Germany's Federal Office for Migration, Jutta Cordt, under pressure.

Interior Minister Horst Seehofer's ban came Wednesday after an internal revision of 4,568 asylum cases found officials at the Bremen branch had intentionally violated regulations.

Seehofer said the "trust in the quality of the asylum procedures and the integrity of the welcome center in Bremen has been massively damaged."

In April, prosecutors said at least 1,200 asylum requests, mostly by members of Syria's Yazidi minority, may have been wrongly approved between 2013 and 2016.