The plan to release the 57-year-old Mohnhaupt, who was once considered Germany's most dangerous woman, on parole has caused widespread controversy.

Mohnhaupt, who was convicted for her role in nine murders in the left wing group's campaign against the West German state in the 1970s, was released from a prison in southern Germany in the early hours, justice official Wolfgang Deuschl said.

"Frau Mohnhaupt has been freed," he told reporters, adding that the woman was collected at the prison by friends.

A German court last month granted her parole because she has served her minimum sentence and is no longer considered a threat. But the families of the victims of the RAF, also known as the Baader-Meinhof Gang, have bitterly opposed the release, partly because Mohnhaupt has never expressed remorse for the murders.

She was part of the second generation of RAF leaders who took over after Ulrike Meinhof, Andreas Baader, Jan-Carl Raspe and Gudrun Ennslin were caught and committed suicide in jail.

RAF no less bloody under Mohnhaupt

The RAF's campaign reached a bloody crescendo in the so-called German Autumn in 1977 when they kidnapped and killed leading industrialist and former Nazi Hanns-Martin Schleyer and hijacked a Lufthansa passenger plane with the help of Palestinian militants.

Schleyer's widow was among those who opposed Mohnhaupt's release, saying she was "appalled" at the move.

The RAF is believed to have killed 34 people. Its other victims include the head of Dresdner Bank, Jürgen Ponto, who was shot dead on his doorstep.

The group also launched attacks against US military personnel stationed in Germany.

In 1981, Mohnhaupt helped to launch a rocket attack on an American general, Frederick Kroesen. He barely survived.

The former philosophy student was finally arrested at an RAF arms cache in a forest near Frankfurt in 1982.

Her release had initially been scheduled for Tuesday. Mohnhaupt has given no indication of what she wants to do outside prison.

Priest convinced Mohnhaupt is rehabilitated

A priest who has regularly visited her in prison in Bavaria in southern Germany over the past 15 years, said she was a "very nice" person who would lead a peaceful life, like other former RAF activists who had completed their prison sentences.

"The RAF has renounced violence and Brigitte Mohnhaupt did so along with them," priest Siegfried Fleiner told reporters. "She is an independent and intelligent woman," he added.

Fleiner said he believed Mohnhaupt will find it difficult to re-adjust to life outside prison but added: "Lately she has been reading several newspapers a day. She is very well-informed about world events."

The RAF disbanded in 1998, but the hardliners and their class war still fascinates Germans.

In recent days newspapers have recalled the violence-filled German Autumn in detail.

RAF comrade Klar remains in jail

Some 20 former militants of the group have been freed after serving lengthy sentences. Only three still remain behind bars, including Christian Klar who led the group along with Mohnhaupt.

Klar was last month refused prison day releases after calling for "the total defeat of the capitalists' aims" in a speech read out on his behalf at a Marxist meeting in Berlin.

Mohnhaupt's release comes as Italy is again confronted with the memory of the Red Brigades, who conducted a similar anti-capitalist struggle in the 1970s, with the arrest of fugitive Cesare Battisti who was long sheltered in France.