Turkish media say authorities have formally arrested two retired Turkish generals in connection with an alleged plot to overthrow the Islamic-leaning government.

Police escort retired army commander Hursit Tolon after a medical check in Ankara, Turkey, (File)

The state-run Anatolia news agency Sunday said a Turkish court ordered former generals Sener Eruygur and Hursit Tolon arrested on charges of forming and leading a terrorist organization.  The news agency said the two are being held at an Istanbul jail.

Lawyers for the generals denied what they called "false accusations" and said they would appeal the ruling.

The generals were among 21 people detained Tuesday in a police investigation against suspected members of a hard-line secularist network known as Ergenekon.  

Authorities say the suspects planned to stage illegal protests across Turkey on July 7, carry out assassinations and trigger battles with security forces.

Eleven of the detainees have been released.  But some of them, including the Ankara representative of a secularist newspaper Cumhuriyet, have been barred from leaving the country while the case continues.

Opposition groups have called the arrests part of a government campaign to intimidate critics.  A ruling party official, Dengir Mir Mehmet Firat, has said the government is acting according to its obligations.

Some information for this report was provided by AFP, AP and Reuters.