BUDAPEST (JTA) — A far-right rally may go ahead in Budapest Saturday on the eve of the World Jewish Congress Plenary Assembly despite a prior police ban.

The Budapest Public Administration and Labor Affairs Court on Friday struck down the ban on the demonstration, saying that “conduct by police, banning the event on the basis of unfounded presumptions, represented a serious violation of the law.”

The rally, scheduled to take place near parliament, is to include speeches by leaders of the radical nationalist Jobbik party, which billed the event as a “Commemoration for the Victims of Bolshevism and Zionism.”

But Prime Minister Viktor Orban — who had ordered the police to ban the rally and any other disturbance around the WJC meeting — called the court’s decision to allow the protest “unacceptable” and urged the Supreme Court and Interior Ministry to prevent it from taking place.

In a statement, Orban said he had “instructed the interior minister to use all lawful means to prevent the event, which goes against the constitution.”

More than 500 Jewish leaders from around the world are expected at the WJC assembly, which opens Sunday night with a speech by Orban. The WJC is holding is session in Budapest to show solidarity with Hungarian Jews after a series of anti-Semitic incidents and to focus attention on the rise of right-wing extremism.