The army has been an untouchable power throughout its life and absolute power corrupts absolutely

General Jose Francisco Gallardo

He hugged his eight-year-old daughter, born three weeks after he began his jail sentence, as he left the prison close to Mexico City.

"This is a victory but this is just part of our struggle," he said.

"The army has been an untouchable power throughout its life and absolute power corrupts absolutely. It must come under democratic control," he said.

Mexican Interior Minister Santiago Creel said President Fox had decided to reduce the sentence being served to eight years, meaning he was free to leave.

"Now we can hold our head up high and face the world and say that the protection and defence of human rights are promoted in Mexico," said Mr Creel.

Threat of legal action

Pressure for General Gallardo's release had been mounting for several months.

Fox has recently released two jailed environmentalists

A number of deadlines set by human rights organisations had come and gone and President Vicente Fox's government was under threat of being taken to the Inter-American Court of Human Rights over the issue.

When the general was sentenced he repeatedly stated that his military superiors had invented the charges to silence him after he had called for an ombudsman to look into human rights abuses by the army.

General Gallardo had previously rejected informal offers of a presidential pardon, insisting he would accept nothing less than formal recognition of his innocence.

The BBC's Nick Miles in Mexico City says the move shows the government intends to send a clear signal that it is prepared to deal with alleged injustices of the past.

Authoritarian legacy

President Fox came to power just over a year ago promising to look into human rights abuses committed during the 70-year rule of the Institutional Revolutionary Party.

In November he bowed to international pressure on another high-profile human rights case by releasing from prison two peasant farmers who led an environmentalist campaign against illegal logging.

Human rights groups have welcomed the news of the latest release, but our correspondent says they are expected to call for further moves to address Mexico's legacy of authoritarian rule.