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 opposition conservatives won parliamentary approval on Wednesday for a proposal to drastically restrict migration with the help of votes from the Alternative for Germany (AfD), breaking a taboo on cooperation with the far-right.

Chancellor Olaf Scholz's main challenger in Germany's upcoming election plans to put proposals for a tougher migration policy to parliament on Wednesday, a maneuver aimed at piling pressure on the governing parties that has brought accusations that he's breaking commitments to shun the far right.