The chairman of Ankara's Chamber of Commerce Sinan Aygun was among the four arrested today.

Turkish media said those detained were suspected of being members of a shadowy, ultra-nationalist, hardline secularist group known as Ergenekon, which was already under investigation.

A secret plan, including launching illegal protests on July 7 across 40 provinces, assassinations and clashes with security forces, was seized during Tuesday's raid, media said.

Agencies