President Vicente Fox freed Rodolfo Montiel and Teodoro Cabrera last fall after the pair spent two and a half years in prison on charges of growing marijuana and carrying illegal weapons.
Fox said he made his decision based solely on medical grounds and stopped short of asking the courts to re-examine the case and acquit or dismiss the charges against Montiel and Cabrera.
Montiel has an intestinal tumor, and Cabrera suffers from cataracts.
Since their release, the activists have presented a string of legal appeals seeking acquittals and asking that federal investigators look into their claims that they were tortured by soldiers who arrested them in 1999.
The latest of those appeals was thrown out last week by a court in the southern state of Guerrero.
Last year, army investigators examined charges that soldiers beat Montiel and Cabrera into confessing to wrongdoing, but found no evidence torture had occurred.
At a news conference, the Miguel Agustin Pro Juarez Human Rights Center said it would ask the Costa Rica-based Inter-American Court on Human Rights to issue acquittals for Montiel and Cabrera.
The group, which has represented the activists since their initial arrests, also said it hoped the international court would investigate Montiel and Cabrera's claims of torture and order the government to pay the pair "a fiscal and moral compensation" for the suffering they endured in prison."These men need a clear declaration of their innocence, and they need justice to be served in their case," Pro Juarez director Edgar Cortez said. "That has not happened in their own country."
Staunch defenders of Guerrero's old-growth fir forests, Montiel and Cabrera led human chains of farmers that blocked logging roads in 1998. After they were jailed, human rights groups around the world dubbed them prisoners of conscience and petitioned for their release.
Speaking by telephone to assembled journalists, Montiel said he was tired of "being viewed as a criminal by the government." "I would ask President Fox to stop saying the human rights situation has improved and that things have changed in Mexico," said Montiel, who refused to disclose his whereabouts, saying that logging interests could come after him. "His government continues covering up for the soldiers that tortured us."
Fox, who ended 71 years of single-party rule in Mexico upon taking office in Dec. 2000, has publicly called his decision to free Montiel and Cabrera a "victory for human rights." Montiel said he had not received death threats since being released from prison but that he and Cabrera hadn't returned to Guerrero because "to do so would be like putting our heads in the wolf's mouth."