LONDON (AP) _ In a surprise decision, Britain ordered ailing IRA suspect Roisin McAliskey freed Monday rather than extradited to Germany, where she was wanted in connection with an attack on a British army base.

Home Secretary Jack Straw said his decision that it would be ``unjust and oppressive'' to extradite McAliskey, 26, was based on medical grounds.

McAliskey was pregnant when she was arrested in Northern Ireland in November 1996 and gave birth to a daughter under armed guard in May. She has been hospitalized in London since shortly before that.

Doctors say she suffers from post-partum depression and eating disorders, and is also being treated for post-traumatic stress syndrome. Hospital officials said she was likely to remain there for treatment.

Straw ``has explained his decision to the German government,'' the Home Office said in a statement. ``It does not reflect in any way on the fairness of the German legal system or on the quality of the extradition request.''

Government spokesmen refused to comment on whether the announcement was timed to affect the Northern Ireland peace talks.

The IRA-allied Sinn Fein party announced Monday that it would not attend the talks until its leaders could meet with British Prime Minister Tony Blair. They want reassurance that their demands _ which had included McAliskey's immediate release _ would be addressed.

German authorities wanted to question McAliskey about an Irish Republican Army attack on a British army barracks at Osnabrueck in June 1996. Nobody was injured but buildings were damaged.

McAliskey has denied involvement.

A court ruled last year that she could be extradited to Germany, but Straw has the final say over such matters.

McAliskey's mother, former nationalist lawmaker Bernadette Devlin McAliskey, said she was relieved and delighted.

``We can now concentrate on getting her well again,'' she said by telephone from her home in the Northern Ireland town of Coalisland.

She believes her daughter was singled out because of the family's anti-British background. Besides her own activism, Sean McCotter, the baby's father, is a former IRA prisoner.

John Wadham, director of the civil rights group Liberty, said Straw's decision ``should have been taken many months ago but it's still important that it's happened now.''