BERLIN — Germany's parliament is expected to vote Friday on an opposition bill calling for tougher rules on migration that could become the first legislation to pass thanks to a far-right party — adding to a controversy about the attitude of the front-runner in Germany's upcoming election toward the far right.

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.

The former chancellor's comments come after the CDU put forward a proposal which was supported by the far-right AfD.

Hundreds of people gathered outside the headquarters of Germany's opposition Christian Democrats (CDU) in Berlin on Wednesday evening to protest against the conservative bloc pushing through a motion to tighten migration policy with the help of votes from the far right.

Protesters in Berlin gathered outside CDU headquarters.Thousands of demonstrators gathered in Germany on Thursday to protest the conservative Christian Democratic Union and Christian Social Union parties.

Thousands of people gathered in front of the headquarters of Germany's Christian Democrats (CDU) in Berlin on Thursday evening after it relied on the far-right Alternative for Germany (AfD) to pass a divisive motion in parliament the day before.