An Egyptian court has found three Al-Jazeera journalists guilty of "spreading false news" and has sentenced them to three years in prison. The retrial of Egyptian-Canadian national Mohammed Fahmy, Australian journalist Peter Greste and Egyptian producer Baher Mohammed had been delayed 10 times this month, but the court delivered the verdict on Saturday morning, according to Al-Jazeera.

The Al-Jazeera staff members are accused of aiding the Muslim Brotherhood, which was outlawed and branded a terrorist organisation after the Egyptian army overthrew Islamists President Mohamed Morsi in 2013. The journalists and Al Jazeera have strenuously denied all accusations made during the trial.

The verdict was criticised by human rights lawyer Amal Clooney, who is representing Fahmy. "The verdict today sends a very dangerous message in Egypt," she said. "It sends a message that journalists can be locked up for simply doing their job, for telling the truth and reporting the news. And it sends a dangerous message that there are judges in Egypt who will allow their courts to become instruments of political repression and propaganda."

Al-Jazeera English acting director-general Mostefa Souag also said: "Today's verdict defies logic and common sense. Our colleagues Baher Mohamed and Mohamed Fahmy will now have to return to prison, and Peter Greste is sentenced in absentia.

"The whole case has been heavily politicised and has not been conducted in a free and fair manner. There is no evidence proving that our colleagues in any way fabricated news or aided and abetted terrorist organisations and at no point during the long drawn out retrial did any of the unfounded allegations stand up to scrutiny.

"A report issued by a technical committee assigned by the court in Egypt contradicted the accusations made by the public prosecutor and stated in its report that the seized videos were not fabricated. Baher, Peter and Mohamed have been sentenced despite the fact that not a shred of evidence was found to support the extraordinary and false charges against them."

The three Al-Jazeera journalists were originally sentenced to up to 10 years in June 2014. But their convictions were overturned in January 2015 and they were freed in February to await retrial.

Greste was allowed to return to Australia, but Fahmy and Mohammed were forced to remain in Egypt on bail. Fahmy revoked his Egyptian nationality in order to qualify for deportation, but it was not clear why he was not deported.

Upset about Al-Jazeera's handling of the case, Fahmy has filed a lawsuit in Canada seeking $100m from the broadcaster, saying that it put the story ahead of employee safety and used its Arabic-language channels to advocate for the Brotherhood. Al-Jazeera has said Fahmy should seek compensation from Egypt.

It had been reported that the journalists were caught up in the wider conflict between Egypt and Qatar following the ousting of Morsi, who was backed by the regime in Doha. During the trail, Egyptian prosecutors used news clips about an animal hospital with donkeys and horses, and another about Christian life in Egypt, as evidence they broke the law. The judges and defence lawyers dismissed the footage as irrelevant.