Details of Mexico's Dirty Wars From 1960s to 1980s Released

Edgar Cortez, executive secretary of the National Network of Human Rights, a coalition of 56 groups, said the low-key release of the report -- sharply contrasting with the fanfare with which Fox promised to dredge up the past -- was troubling. He said he wonders whether it signals the end of the process, instead of the beginning of justice.

"It can be an advance," he said of the report, "but for us the problem is that in the end, it's a report with no guarantees."

The Mexican government had never admitted that there was a clear and comprehensive plan designed to root out enemies of the state and silence them. Officials have blamed rogue army units or overly aggressive military officers for abuses.

But the report says that governments "at the highest command levels" carried out crimes against opponents.

Among the more egregious abuses examined in the document was the 1968 massacre of dozens of people at the Tlatelolco Plaza in Mexico City, an assault prosecutors believe was engineered by Luis Echeverria, at the time the interior minister.

During Echeverria's tenure as president, which began in 1970 and ended six years later, the Mexican military carried out a vicious counterinsurgency campaign in the southern state of Guerrero that led to the deaths of hundreds.

The abuses outlined in the report took place during the administrations of Gustavo Diaz Ordaz (1964 to 1970), Echeverria and José López Portillo (1976 to 1982).

Only Echeverria is alive, but efforts to try him for the crimes have failed. A judge threw out genocide charges this summer, saying a statute of limitations had run out.

Researcher Gabriela Martinez in Mexico City contributed to this report.