Thomas Hammarberg, the Council of Europe's commissioner for human rights, today published his summary of findings of a visit he made to Armenia in the summer.
At least 10 people were killed in the March clashes between police and protesters who accused the government of rigging February's presidential election in favor of the winner, Serzh Sarkisian.
Hammarberg said he was particularly concerned about seven people who remained in preliminary detention, including prominent opposition members.
"It is unacceptable to continue to hold in detention or to convict -- even to noncustodial sentences -- anyone solely because of their political beliefs or nonviolent activities," he said.
He also said it was regrettable that 19 people were being prosecuted based solely on police testimony.
"The situation of persons deprived of their liberty continues to be a source of serious concern" Hammarberg said. "Questions persist as to the very nature of the criminal charges and the intent of the investigations carried out."