"We must emphasize that, in general, this is quite a complex case," prosecutor Franklin Alborta told reporters. "Preliminarily, we are reporting that more than 30 people are already formally under investigation," he said.

One of the suspects arrested as recently as Monday was Vladimir Lupa Salamanca, commander of F10, an elite group of the armed forces, Xinhua news agency reported.

He is scheduled to testify before prosecutors in La Paz.

The main defendants include former army commander and coup leader General Juan Jose Zuniga, former navy commander Juan Arnaez and former air force commander Marcelo Zegarra.