Two prominent Turkish journalists charged with aiding a shadowy group aiming to topple the Islamist-rooted government went on trial Tuesday as press freedom campaigners demonstrated outside. Award-winning reporter Nedim Sener and dissident journalist Ahmet Sik were in the Istanbul court for their first hearing along with 12 other defendants in the case which has sparked international concern. Defence lawyers immediately sought the release of their clients, who face a maximum penalty of 15 years in jail for aiding an armed group if convicted Sener, who won the International Press Institute's World Press Freedom Hero award in 2010, and Sik, known for his reporting on human rights and other abuses, have been in custody since March. They face charges of helping Ergenekon, a hardline nationalist group accused of plotting assassinations and bombings to throw Turkey into chaos and trigger a military coup against the ruling Justice and Development Party (AKP). Sener had won a press freedom award for a book he wrote on the murder of ethnic Armenian journalist Hrant Dink. Among the book's claims is that security forces ignored intelligence about plans to murder Dink and paved the way for his assassination. When he was arrested, Sener claimed that he was chosen as a target because he disclosed the wrongdoings of some significant security officials in Dink's murder. Sik was credited before with being among the first journalists to report that some generals were plotting to oust the government, months before police in 2007 initiated a probe into Ergenekon gang. Sik and Sener are accused of being part of the media branch of the gang and of fabricating information on behalf of the gang, according to the indictment, Anatolia news agency said. In March, a court ordered the seizure of all the copies of a draft book Sik prepared about the infiltration of Islamist circles in the police force. The court concluded that the book was "clear propaganda" of the gang. Outside the court, some 200 journalists and human rights activists demonstrated to demand the release of the defendants. "No free society without freedom of the press," one banner read. The journalists' arrest sparked widespread concerns about freedom of expression in Turkey, which was also underscored in a report by the European Commission last month on the status of Ankara's EU membership bid. Prime Minister Recep Tayyip Erdogan, leader of the AKP, has insisted that nobody has been jailed in Turkey because of their profession as a journalist but because of their membership of an illegal organisation. The defendants' lawyers also asked for the dismissal of the judges in the case. Among the lawyers' reasons for their demand is that one judge, Ali Fuat Yilmaz, was among the judges hearing the murder case of Dink and he had neglected his duty during the trial. "Where is the evidence that the prosecutor had promised to justify the imprisonment of journalists?... The indictment shows that it is for journalistic activities that journalists are in prison and this is totally unacceptable," Johann Bihr of Reporters Without Borders told AFP out of the court. Some 70 journalists are currently in jail in Turkey, including at least 15 or 20 because of their journalistic activities, according to Bihr. "That sort of record is not really compatible with a country that seeks to promote democracy and freedom of expression," said Stephen M. Ellis, of the International Press Institute. The second hearing in the case will be held on December 26, while a higher court will discuss lawyers' demands to dismiss the judges.