The retrial of three Al Jazeera journalists has been adjourned for a tenth time in Egypt.

The court in Cairo said on Sunday that a verdict in the case would now be delivered on August 29.

Egyptian Baher Mohamed, Canadian Mohamed Fahmy and Australian Peter Greste were found guilty in June 2014 of aiding a terrorist organisation, a reference to the Muslim Brotherhood, which was outlawed in Egypt after the army overthrew President Mohamed Morsi in 2013.

Greste and Fahmy received seven years, while Mohamed was given 10 years.

After the announcement that the trial had once again been adjourned, Greste described the situation as "frustrating as hell".

He said that until there is a verdict, none of the accused can move on with their lives.

Verdict postponed until August 29th The audacity & continuous disrespect to our rights is unprecedented! #FreeAJStaff #Judgenot #Egypt — Mohamed Fadel Fahmy (@MFFahmy11) August 2, 2015

In January, an appeals court ordered a retrial, saying the initial verdict lacked evidence against the three journalists working for the Doha-based network's English channel.

Greste has already been deported to his native Australia under a law allowing the transfer of foreigners on trial to their home countries but he is still being retried in absentia.

'Kafkaesque' process

Fahmy and Mohamed were freed on bail in February after spending more than 400 days in detention.

Fahmy renounced his Egyptian nationality hoping he too would be deported.

Giles Trendle, acting managing director of Al Jazeera English, said the trial had been "almost Kafkaesque in some of the ludicrous groundless charges, in some of the strange decisions, even in the delays that you are seeing, just adjournment, ad infinitum".

He also thanked all those who have supported Al Jazeera's campaign demanding the release of its journalists.

"There has been a tremendous campaign and we thank everybody who has been behind that campaign: world leaders, international media, human rights organisations, general public as well as our own staff of course ... The campaign will go on until we can get justice for our people."

Al Jazeera's Peter Greste: Delay is 'frustrating as hell'

Nicolas Piachaud, Egypt analyst at Amnesty International, said the Al Jazeera case was just "the tip of an iceberg" as there are 20 other journalists currently in jail in Egypt.

The US-based Committee to Protect Journalists (CPJ) said in June that journalists in Egypt face unprecedented threats, with the highest number behind bars in the country since it began keeping records in 1990.

In a report detailing the incarceration of 18 Egyptians, the CPJ said most were accused of affiliation with the Muslim Brotherhood.

The group said that in addition to imprisoning journalists, authorities pressure media outlets to censor critical voices and issue gag orders on sensitive topics.

President Mohamed Morsi of the Muslim Brotherhood was overthrown by the army in 2013 following protests against his rule.

Since then, authorities have cracked down on the Muslim Brotherhood and other opponents, killing hundreds and jailing thousands.