The trial has begun in Burundi for 28 people accused over May's attempt to oust President Pierre Nkurunziza.
The defendants include Burundi's former defence minister Cyrille Ndayirukiye and 27 other senior military and police officials.
The trial comes amid rising concern over the security situation in the country.
Protests in Burundi began in April when the president announced he would seek a third term in office.
The 28 standing trial at the supreme court in the central town of Gitega have also been accused of inciting killings and destroying property during the anti third-term protests.
Mr Ndayirukiye and the other accused told the court they had been kept in isolation in "inhumane conditions", and had been forced to defecate in a bucket, the BBC's Prime Ndikumagenge reports from the capital, Bujumbura.
They said they would not enter a plea until their prison conditions were improved, our correspondent adds.
On Friday, 87 people were killed after three military sites were attacked, Burundi's army said.
The army says those killed in Friday's violence were criminals, but residents accuse the security forces of extra-judicial killings.