Scuffles broke out between police and demonstrators outside a prison complex in Turkey Monday where nearly 10,000 people protested the mass trial of 275 people accused of scheming to topple the elected Turkish government.

An AFP photographer saw protesters trying to breach the security barricade outside the compound in Silivri, a suburb on the outskirts of Istanbul.

The protest was called by opposition groups and political parties as an Istanbul court prepares to hear the closing arguments in the four-year-long trial of the defendants who stand accused of having ties to an ultranationalist "terrorist network" known as Ergenekon.

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.