Al-Jazeera journalists, including four foreigners, go on trial in Cairo Thursday for allegedly supporting the blacklisted Muslim Brotherhood in a case that has sparked accusations Egypt is muzzling the media. The trial of journalists for the Qatar-based channel comes against the backdrop of strained relations between Cairo and Doha, which is a backer of Islamist president Mohamed Morsi, ousted by the army in July, and of his Muslim Brotherhood. Prosecutors allege that the defendants, including award-winning Australian Peter Greste and Egyptian-Canadian Mohamed Fadel Fahmy, manipulated footage and supported the Brotherhood, which was banned after Morsi was deposed. In all, 20 "Al-Jazeera journalists" are on trial, but only eight of them are in custody. Prosecutors say they falsely portrayed Egypt as being in a state of "civil war", possibly a reference to the broadcaster's coverage of a crackdown that has killed more than 1,000 Morsi supporters in street clashes. The government has designated the Brotherhood as a terrorist organisation, although the group denies involvement in a spate of bombings since Morsi's overthrow. Al-Jazeera, which says only nine of the defendants are on its staff, has denied the charges. Greste, a former BBC correspondent, and Fahmy, who worked with CNN before joining Al-Jazeera, were arrested in a Cairo hotel in December. The other foreign journalists listed in the indictment are abroad and will be tried in absentia. They are Britons Sue Turton and Dominic Kane and Dutch journalist Rena Netjes, who was indicted even though she does not work for the channel. The United States, press freedom groups and scores of journalists have protested against the detention of the reporters. On Wednesday, the International Press Institute urged the court to release the journalists. It said a fact-finding trip suggested that "security forces have been systematically accusing journalists of unsupported charges of aiding terrorists or spreading 'false news' in an effort to frighten all journalists and hinder independent news-gathering." Greste himself, in a letter written from prison that was published last month by Al-Jazeera, described what he sees as a lack of press freedom in Egypt. "The state will not tolerate hearing from the Muslim Brotherhood or any other critical voices," he wrote. "The prisons are overflowing with anyone who opposes or challenges the government." None of the arrested journalists appeared to have been working with press accreditation. Egyptian officials insist the channel has been working for the benefit of Qatar, a strong supporter of the Muslim Brotherhood that has even hosted some of its members who have fled the crackdown. "It is a Qatari network and Qatar is the only Gulf Arab country supporting the Muslim Brotherhood," a high-ranking official told AFP on condition of anonymity. In the past, Al-Jazeera, especially its Arabic-language service, has come under criticism for allegedly biased reporting in the Arab world.