AMSTERDAM (Reuters) - Dutch anti-Islam politician Geert Wilders began his appeal on Thursday against a conviction for inciting discrimination, accusing prosecutors of trying to destroy his right to free speech.

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Wilders, whose party finished second in an election last year, is the leader of the opposition in the Netherlands and one of the leading figures in Europe’s far right.

“What the Islamists haven’t been able to do to me, the prosecutors are trying to do anyway: destroy freedom of expression,” Wilders said on Twitter before the start of Thursday’s hearing, held in a special high-security courtroom near Amsterdam’s Schiphol airport.

Wilders is appealing against his 2016 conviction for inciting discrimination, over a campaign rally at which he asked supporters whether they wanted more or fewer Moroccans in the country. When they chanted “Fewer! Fewer!” he replied: “We’re going to take care of that.”

His lawyer Geert-Jan Knoops argued at the start of proceedings that the criteria that determined whether speech was discriminatory were hazy and had been “selectively applied” against Wilders.

To support his argument, he highlighted the fact that prosecutors chose last month not to bring a case against Wilders’ biggest domestic political rival, Alexander Pechtold of the centrist D66 Party, over comments this year that were possibly insulting to Russians, despite people’s complaints.

He asked for a delay in proceedings until prosecutors released information about that case. Pechtold was never formally accused of any wrongdoing.

Prosecutors are also appealing against Wilders’ acquittal over separate charges of inciting hatred. Prosecutors have sought a fine of 5,000 euros ($5,910) but no jail time.

Article 1 of the Dutch constitution forbids discrimination on any grounds. Wilders says he has never called for violence and the number of Moroccans in the country could be reduced by legal means. He was previously acquitted of hate speech in 2011.

The appeals hearings run through June 6, with a verdict expected a month later.

Wilders has lived in safe houses under 24-hour guard since 2004 to protect him from Islamist militants who threaten to kill him. He says Islam is a fascist ideology, and has called for halting immigration from Muslim countries, shutting mosques and banning the Koran.