The trial of 86 people in Turkey on charges including armed insurrection and aiding a terror group has adjourned after chaotic opening scenes.
The judge called a halt for several hours, and ordered everyone out, after lawyers complained that conditions in the court were intolerable.
The suspects are accused of belonging to a shadowy ultra-nationalist network.
Prosecutors say the group plotted a series of attacks aimed at provoking the military into carrying out a coup.
The trial may revive tensions between the Islamist-rooted ruling AK Party and the secular military, analysts say.
Among the 86 suspects charged at the Silivri prison-court were retired army officers, politicians, academics and also journalists, who are alleged to be members of the Ergenekon group.
The 2,455-page indictment holds the group responsible for at least two violent attacks - a bombing of a secularist newspaper in 2006 and an attack on a court the same year in which a judge was killed.
The trial is being held at Silivri prison in Istanbul
The attacks on these key parts of the secular establishment were supposed to provoke the military into launching a coup in defence of secular interests, it is alleged.
The suspects deny the charges, saying they are politically motivated.
As the trial opened, the presiding judge asked spectators and reporters to leave the tiny courtroom, amid protests by defence lawyers that they could not work in such conditions.
Outside the courtroom, scores of demonstrators with Turkish flags held a protest rally. Many of them chanted: "The traitors are in parliament, the patriots are in prison."
As proceedings began to descend into disarray, the presiding judge decided to halt them for several hours.
The trial resumed in the afternoon, with the judges ordering out everyone except the 46 prisoners who are in custody, their lawyers and the press.
A video screen will be set up in an adjoining room for future hearings for the 40 defendants who are on bail and the families of defendants.
One defendant, Capt Muzaffer Tekin, told the judges: "An imaginary group has been invented. I am accused of being a leader of this group but I don't even know this group. I see this as a political plot."
The case was later adjourned until Thursday.
The remaining defendants, who are not being held, will give testimony in separate hearings.
The trial is unusual in a number of ways: the sheer size of it and the fact that the defendants include retired Turkish military officers, the BBC's Pam O'Toole says.
This is something that would have been unthinkable only a few years ago, given the power of the military, which has mounted three coups since 1960 and, in 1997, eased the country's first pro-Islamist prime minister from power, our correspondent says.
PM Recep Tayyip Erdogan insists he does not have an Islamist agenda
Then there is the nature and scope of the charges, some of which would not seem out of place in a Hollywood thriller, she adds.
But many Turks regard the trial as the latest stage in an ongoing power struggle between Turkey's secular nationalist establishment and the governing AKP.
The alleged plotters were indicted this summer, shortly before the ruling in a court case that was aimed at closing down the AKP for allegedly becoming a focus for anti-secular activities.
Government critics believed the timing was no coincidence.
Some believe this trial is the AKP's revenge for the Constitutional Court case, which in the end did not succeed in closing the party; others maintain the Ergenekon network simply does not exist.
Government supporters portray it as a step towards accountability and democracy by taking much-needed action against so-called "deep state" nationalist groups that have previously been virtually untouchable.
The military denies any links to such groups.
Turks will watch this case closely, but it could be months, or even years, before there is a result, our correspondent says.
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