Zuniga and others were arrested last June after soldiers and tanks took up positions outside government buildings in what Arce said was an attempt to unseat him.

However, Zuniga claimed he had been following Arce's orders and that the president had hoped surviving a coup would boost his flagging popularity among Bolivians battling surging prices amid shortages of money and fuel.

Bolivia's powerful former president Evo Morales -- with whom Arce is feuding ahead of elections this year -- also accused the president of mounting a "self-coup."

Arce denied he had conspired with Zuniga, who was being held at a maximum security prison, and now faces charges of terrorism and armed uprising, the prosecutor's office told AFP.

An investigating judge will decide whether to put Zuniga on trial.