Istanbul (CNN) -- Turkey's former military chief was behind bars Friday pending trial for his alleged role in a plot to overthrow the government.
Gen. Ilker Basbug is the highest-ranking officer to be accused in a long-running tussle between the Islamic-backed government and Turkey's secular establishment, defended by the military.
Basbug was arrested and taken to Silivri prison after testifying for seven hours Thursday in an Istanbul court, Basbug's lawyer Ilkay Sezer told reporters.
He stands accused of involvement with the so-called Ergenekon network, a nationalist group that prosecutors say created dozens of websites disseminating propaganda aimed at bringing down the government of Prime Minister Recep Tayyip Erdogan.
"The 26th chief of general staff of the Turkish Republic is unfortunately arrested based on charges related to eliminating the government of Turkish Republic and establishing and leading a terrorist organization," Sezer said.
Basbug retired as commander of the Turkish armed forces in 2010. He is the latest in a long line of military staff who stands accused of plotting against the government.
A probe was launched in 2007, after the discovery of a stash of grenades and bomb-making materials in Istanbul.
It led to waves of arrests and several court cases involving both civilians and former and active-duty officers.
More than 300 people have been arrested in connection with Ergenekon. Among them are 97 journalists, according to the Turkish Press Union.
The government's crackdown has polarized Turkish society, which has seen the military overthrow four governments in the past 50 years.
Some view the government's actions in curbing military power as important steps to democratization in Turkey, a candidate for European Union membership.
But critics say the investigation is a political witch hunt. They accuse Erdogan, an observant Muslim, of silencing his opponents and emasculating the secular establishment, including the military.
Last July, Turkey's top four military officers resigned after a squabble with the government over the fate of officers jailed in the alleged plot against the Justice and Development Party.
Friday, Turkish President Abdullah Gul told journalists that Basbug's arrest did not prove guilt.
"No one can be declared guilty before a decision of the court," Gul said. "Everyone is equal in the court of law. This is a legal process."
CNN's Yesim Comert and Talia Kayali contributed to this report.