(CNN) A Turkish court has sentenced 14 employees of a newspaper that has been critical of President Tayyip Recep Erdogan's government to prison, convicting them on 'terrorism' charges.

The lengthy sentences have added to increasing fears over press freedom, particularly with national elections taking place in June.

The defendants were among over a dozen journalists and staff from Cumhuriyet to go on trial, accused of supporting terror organizations in the wake of a 2016 botched coup to oust Erdogan.

The staff of the paper, which has long been critical of the president, were found guilty of supporting the network of Fethullah Gulen, a Turkish cleric living in exile in the US. Erdogan claims Gulen has his supporters were behind the coup attempt, something the Pennsylvania-based cleric has denied.

Purges after the coup

Human rights groups said the sentences are intended to stifle criticism of the government before the snap elections, which Erdogan announced last week.

"These politically motivated sentences are clearly intended to instill fear and silence any form of dissent," said Milena Buyum , Amnesty International's Turkey campaigner.

"This is a shocking affront to press freedom and for justice in Turkey and sets a chilling precedent for scores of other journalists facing trials on similar trumped-up terrorism-related charges," she added.

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In the aftermath of the failed coup, Turkey has been under a state of emergency, and Erdogan has orchestrated a series of controversial constitutional reforms while overseeing a massive purge within government ranks. Critics have argued that martial law was a pretense Erdogan was using to silence the opposition.

Journalists remain defiant

Despite the crackdown Cumhuriyet didn't let up in its scrutiny of Erdogan and his ruling Justice and Development Party. After Thursday's sentencing the newspaper's journalists remained defiant.

"No penalty can stop us from doing journalism. If needed, we will go to the prison again but we will continue to do journalism," Editor-in-Chief Murat Sabuncu, who was sentenced to seven years and six months in prison, told AFP after the verdict.

"These verdicts are entirely unlawful," said Sik's wife, Yonca. "We knew that law never existed but now it's certified."

All but one defendant in the case will remain free pending an appeal.

Three Cumhuriyet employees were acquitted. The trial of two other Cumhuriyet journalists will continue separately.

Fears of press freedom

The case has underscored the dire state of press freedom in Turkey. PEN International, a writers' advocacy group, estimates that over 150 journalists and writers are in prison and more than 180 media outlets and publishing houses have been closed down.

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More broadly, since the failed coup, 100,000 people have faced criminal investigations and at least 50,000 people have been imprisoned pending trial, Amnesty International reports. It says that over 107,000 public sector employees have been summarily dismissed.

June's polls will be the first since a referendum last year that transformed Turkey's parliamentary democracy into a powerful executive presidency, and will hand the president sweeping new powers after the elections.

Under the new system, the president will be able to prepare the budget and appoint high-level officials, including ministers and judges. In addition, the president will be able to declare a state of emergency, a power currently held by the government. The president could also in some circumstances dissolve parliament.