ANKARA, Turkey (AP) — Turkey’s highest court on Wednesday upheld a controversial media law that mandates prison terms for people deemed to be spreading “disinformation,” rejecting the main opposition party’s request for its annulment.

The legislation calls for up to three years in prison for journalists or social media users convicted of spreading information deemed to be “contrary to the truth” concerning domestic and international security, public order or health.

It was approved in parliament a year ago with the votes of legislators from President Recep Tayyip Erdogan’s ruling party and its nationalist allies, heightening concerns over media freedoms and free speech in the country.

The main opposition party had petitioned the Constitutional Court seeking its annulment, arguing that the law would be used to further silence government critics by cracking down on social media and independent reporting.

The court’s justices, however, rejected the request by a majority vote during a meeting on Wednesday, the state-run Anadolu Agency reported. It didn’t elaborate on the ruling.

Around 30 people have been prosecuted under the law since it came into effect last year, the Cumhuriyet newspaper reported.

Last week, authorities arrested investigative journalist Tolga Sardan under the law, accusing him of engaging in disinformation over his report about allegations of corruption within the judiciary.

The journalist, who works for online news website T24, was released days later pending the outcome of a trial, on condition that he reports regularly to authorities. He was also barred from traveling abroad.

Erdogan had long argued for a law to combat disinformation and fake news, saying false news and rising “digital fascism” pose national and global security threats.

Freedom of expression and media freedoms have declined dramatically in Turkey over the years. Reporters Without Borders ranks Turkey 165 out of 180 countries in press freedoms. Currently, 19 journalists or media sector workers are behind bars, according to the Journalists’ Union of Turkey.