A regional branch of a rising German nationalist party is in turmoil over accusations of anti-Semitism against one of its lawmakers.

The three-year-old Alternative for Germany, or AfD, won 23 seats in the state legislature of Baden-Wuerttemberg in a March election amid discontent over Germany's migrant influx. Allegations then surfaced that lawmaker Wolfgang Gedeon had supported Holocaust deniers.

Caucus leader Joerg Meuthen, who is also AfD's national co-leader, last month failed to secure a two-thirds majority to remove Gedeon, although the latter suspended his membership in the parliamentary group.

On Tuesday, Meuthen said he and 12 other lawmakers were leaving the AfD caucus after again failing to get Gedeon ousted. The party's national leadership welcomed the move and said it would only recognize lawmakers who followed Meuthen as AfD representatives.