Turkish police on Monday fired tear gas and water cannons at around 10,000 demonstrators protesting a mass trial of hundreds accused of plotting to topple the government, leading to three injuries and a lengthy delay in the hearing.
An AFP photographer saw protesters trying to breach a security barricade by hurling stones at the police outside the prison complex in Silivri, a suburb on the outskirts of Istanbul.
One demonstrator suffered a non-fatal heart attack and two journalists were injured, CNNTurk channel reported, as police tried to disperse the protesters who waved Turkish flags and chanted "justice for all".
The police resorted to water cannons and tear gas, which spread to the courtroom in wind and led to a more than two-hour delay in the hearing of 275 defendants scheduled for Monday.
The protest was called by opposition groups and political parties as an Istanbul court prepared to hear the closing arguments in a four-year trial of defendants who stand accused of having ties to an ultranationalist "terrorist network" known as Ergenekon.
Hearings are frequently delayed due to similar scuffles breaking out in front of the high-security compound, as well as quarrels inside the volatile courtroom.
The hearing has been postponed to Thursday.
A vast array of top military figures, lawyers, academics and journalists are accused of instigating an uprising against the Islamic-rooted Justice and Development Party (AKP) government, in power since 2002.
If convicted, they face sentences ranging from seven-and-a-half years in prison to life.
Prosecutors last month sought life jail terms for the 64 top suspects, who include former army chief Ilker Basbug and nine other active and former generals, accused of "attempting to overthrow the Turkish government by force".
A final verdict is not expected before a few weeks.
The trial is one of several cases brought by the AKP against the once omnipotent army which has been responsible for four coups in half a century.
In a separate case last year, dubbed the "Sledgehammer" trial after a military exercise, Turkey jailed three former generals for 20 years each and handed prison terms to dozens of officers.