ANKARA, Turkey — A Turkish court on Friday convicted 330 military officers, including the former air force and navy chiefs, of plotting to overthrow the Islamic-based government in 2003, state television reported, in a case that has helped curtail the military's hold on politics.

A panel of three judges at the court on Istanbul's outskirts initially sentenced former air force chief Ibrahim Firtina, former navy chief Ozden Ornek and former army commander Cetin Dogan to life imprisonment but later reduced the sentence to a 20-year jail term, TRT reported. The three were accused of masterminding the plot.

The court also convicted 327 other active or retired officers for involvement in the conspiracy, sentencing some to as much as 18 years in prison. Thirty-four were acquitted while the case against one was postponed for health reasons.