The reclassification — AfD was previously designated a “suspected” extremist group — is likely to reignite debate over a political ban on the party.

The AfD came second in February elections and has a record number of seats in the new parliament.

Germany's domestic security agency classified the Alternative for Germany (AfD) as "extremist" on Friday, allowing for closer monitoring of the country's largest opposition party, which condemned the move as a "blow against democracy".