ISTANBUL (AFP) - Several thousand protesters thronged Istanbul Saturday to demonstrate against government prosecution of a hardline secularist network uniting military, media and business figures, local media reported. The Ergenekon nationalist network is accused by the ruling Islam-rooted Justice and Development Party (AKP) of seeking to overthrow the government, with charges against 86 people being laid this week. The rally " which passed off with any reported incidents " was called by the Ataturk Thought Association (ATA) and held on the Asian shore of the Bosphorus. Protesters held aloft the Turkish flag and chanted slogans denouncing the AKP. "With this investigation they are trying to put pressure on the Kemalists," ATA Vice-President Sina Aksin told the Anatolia press agency, referring to Mustafa Kemal Ataturk, the founder of modern, secular Turkey. The president of ATA, Sener Eruygur, a retired general, is currently in custody charged with "setting up and leading an armed gang" along with 85 other suspects.  The Ergenekon inquiry " viewed by many analysts as a power-struggle between the moderate Islamist govt and the secularist military " has seen the arrest of many well-known figures in Turkey, from military personnel to journalists and business leaders. Some commentators have accused the AKP of using an Ergenekon crackdown to pressure its secular opponents whilst it itself is threatened with a possible ban by Turkey's constitutional court. AKP denies wanting to create an Islamic regime in Ankara, and says it abides by the republic's founding principle of the separation of state and religion. The dates of the first Ergenekon hearings are expected to be made public in the coming days.