A Turkish court has convicted 330 active and retired military officers of charges they planned to overthrow the government.

The court issued the verdicts Friday, initially sentencing the coup leaders – former army commander Cetin Dogan, former air force chief Ibrahim Firtina and former navy chief Ozden Ornek – to life behind bars. It then reduced those sentences to 20 years in prison, because the coup had failed.

Other current and former military officers got lesser sentences. Thirty-four officers were acquitted.

The convictions are the result of a two-year trial of charges connected to 2003's so-called “Sledgehammer” conspiracy. Turkish officials said the military had devised a plot to overthrow the government of Prime Minister Tayyip Erdogan.

Prosecutors said the plot included plans to cause panic across Turkey by triggering a conflict with neighboring Greece and bombing mosques in Istanbul. The ensuing chaos would have allowed the military to launch a coup.

The defendants maintained the so-called plot was just a war games contingency exercise and that the evidence against them has been fabricated. The defendants' lawyers said police acknowledged they had planted incriminating evidence.

Long-running tensions between Turkey's secularist military and Mr. Erdogan's Islamic-rooted government came to a head last month with the sudden resignations of the country's top four military commanders.

The Turkish army has forced four governments from power since 1960.