A group of officers led by a colonel in President Sukarno's palace guard was accused of trying to launch a coup.
General Suharto led bloody anti-communist purges in which hundreds of thousands of suspected leftists were killed.
Many more were detained and imprisoned without trial.
In 1966, President Sukarno was forced to hand emergency powers to Gen Suharto, who took over as president the following year, ruling Indonesia for 31 years.
