Former German Chancellor Angela Merkel has issued rare public criticism of her successor as the country’s center-right leader, the front-runner in Germany’s election next month, for putting to parliament proposals for tough new migration rules that only passed with the help of a far-right party.

Germany’s parliament has narrowly approved a call by Chancellor Olaf Scholz’s main challenger to turn back many more migrants at the country’s borders, with the help of a far-right party.

With less than four weeks before Germany’s federal election, Chancellor Olaf Scholz and his conservative challenger Friedrich Merz, who is leading polls, will take their contentious battle over how to crack down on illegal migration to parliament.