A former regional leader of the Alternative for Germany party has been convicted of incitement to hatred over online posts targeting Muslims.

German news agency dpa reports that a court in the northeastern city of Rostock gave lawmaker Holger Arppe a fine of 9,000 euros ($10,740). Arppe denied having written that Britain should be turned into a "quarantine island" for Muslims living in Europe.

The court ruled Monday that Arppe had posted the comments in 2010 using a pseudonym, rejecting his appeal against a lower court ruling.

Arppe is a member of the regional assembly in Mecklenburg-Western Pomerania state. He left Alternative for Germany last year, saying he wanted to avert damage from the party following the leak of unrelated online chats advocating violence against political enemies and children.