The Federal Prosecutor's Office in Karlsruhe has received over 1,000 complaints for treason against German Chancellor Angela Merkel since 2015, according to a report published Wednesday in the daily Mannheimer Morgen.

Most of the criminal complaints were filed by supporters of the right-wing populist Alternative for Germany (AfD) party.

A spokesperson for the authorites told the paper that all the complaints had "turned out to be baseless." Prosecutors are required by law to investigate any charges pressed.

Read more: How refugees are settling into Germany, two years on

Leading AfD politicians Alexander Gauland and Jörg Meuthen did not want to comment on Mannheimer Morgen's report according to the paper. They had repeatedly criticized Merkel for her decision two years ago to let in nearly 900,000 refugees, while other EU countries barely took in a few hundred or hardly any at all. She insisted that Germany could cope by saying "Wir schaffen das" ("we can manage it").

Speaking at her annual summer news conference on Tuesday, Merkel said the wave of refugees in 2015 was a "humanitarian exception," and that she had to act immediately. She also chided other EU states for not pulling their weight on this issue.

In 2015, Merkel had argued that any EU member state was allowed to help another member state take in refugees in an emergency, thereby skirting the Dublin regulation for asylum seekers. 

In July 2017, the European Court of Justice upheld the regulation, which stipulates that migrants must seek asylum at the point of entry into the EU. But the court also said that asylum seekers should not be transferred back to the member state responsible if that country cannot provide adequate care due to, for example, a large influx of refugees.

The refugee crisis had led to a dip in the ratings for Merkel's Christian Democratic Union (CDU), but the latest polls show a comfortable lead for the party ahead of the September 24 national elections.