"An official has announced the release of 86 detainees after legal steps have been taken against them," the ministry said in a post on Twitter.
The opposition said that around 400 people were arrested during protests that erupted in the kingdom on Feb. 14.
The government has said that 24 people were killed during the protests, four of them policemen, while three other activists have died in custody.
The Interior Ministry said in another Web statement that Bahrain's leading human rights activist will be questioned by a military prosecutor.
The ministry accused Nabeel Rajab, head of the Bahrain Center for Human Rights, of tampering with photos of a man who died in custody last week. A ministry statement said Rajab posted on his Twitter account a "fabricated image" of a detainee, Ali Isa Saqer.
Rajab claims Saqer was fatally beaten in custody. He told The Associated Press that the photo he had posted on his Twitter account was genuine, showing Saqer's body covered with bruises and gashes.
Authorities claim Saqer died Saturday after struggling with guards. A government photo shows few signs of injuries.
Rajab said the campaign against him is aimed at preventing him from documenting human rights abuses in Bahrain.
