A Chilean judge has ordered the arrest of almost 100 former soldiers and secret police over rights abuses dating from General Augusto Pinochet's government.
Victor Montiglio ordered the detentions as part of a probe into the kidnappings and murder of scores of opponents of Pinochet during "Operation Colombo" in 1975.
It is thought to be the largest mass arrest of suspects relating to rights abuses from the period.
"This is excellent news, because Operation Colombo was also a case in which General Pinochet's immunity from prosecution was stripped and - given the number of victims - is an emblematic case," Sergio Laurenti, executive director of Amnesty International in Chile, told Reuters news agency.
"But it is important that the police now furnish the necessary information to enable the courts to proceed," he said.
"There is a lack of co-operation from the armed forces and security forces."