The World Jewish Congress has reported a statement by the Budapest chief prosecutor that a Budapest court has ordered the temporary shutdown of nearly two dozen websites that carry content denying the Holocaust.

The websites sell the Hungarian edition of a Swedish author’s book that denies the Holocaust and other crimes committed by the Nazi regime, prosecutor Tibor Ibolya said. The sites also make some of that content available online.

The Hungarian authorities also started investigating the book’s publisher in Hungary but suspended the procedure because the company’s head is currently abroad.

Under a 2010 Hungarian law, Holocaust denial in public is a crime punishable by up to three years imprisonment.

About 600.000 Hungarian Jews were killed in the Holocaust.