Attempts by a Spanish judge to bring Argentina's former military rulers to justice in Europe have suffered setbacks.

State prosecutors in Madrid say they will try to block international arrest warrants issued by the judge Baltasar Garzon for almost one hundred former officials accused of crimes against humanity.

They say he has no jurisdiction to try the officials.

At the same time, a former Argentine navy captain whose evidence had helped the judge build his case, has retracted his testimony.

The captain Adolfo Scilingo had admitted participating in flights in which dissidents were thrown out of aeroplanes.

But he's now been quoted by his lawyer as saying that he had been the victim of a conspiracy. Mr Scilingo remains in Madrid after giving his testimony last year and was among those named by the judge on Tuesday.