BERLIN (AP) _ A German engineer suspected of selling nuclear technology to Iraq was ordered jailed today, a day after he returned home from Brazil and gave himself up so he could visit his terminally ill mother.

Karl-Heinz Schaab was arrested at Frankfurt airport Thursday after arriving on a Lufthansa flight from Sao Paulo, Brazil.

Federal prosecutor Kay Nehm said Schaab, who has been under investigation for treason since 1995, is suspected of helping Iraq produce weapons grade uranium in 1989-90.

The 64-year-old engineer allegedly sold Iraq construction plans for a uranium enrichment plant for $1.2 million. The plans were found by U.N. inspectors in Iraq.

Schaab denies the information he provided was ``secret enough to justify this serious charge,'' his lawyer, Michael Rietz, said in a telephone interview.

While admitting he bears ``moral guilt'' for helping Iraq with what he saw at first as a ``technical challenge,'' Schaab also insists others were involved and his own role was minimal, Rietz said.

``The Iraqis didn't just run around and ask him, `Will you help us develop our atomic weapons program?''' Rietz said. But by the time Schaab realized what they were up to, ``he was maybe in too deep.''

He said Schaab's firm also was having financial problems at the time and Schaab needed money.

Schaab, who was placed on probation after a 1993 conviction for violating export laws, disappeared from his home in the Bavarian town of Kaufbeuren in January 1996.

He was arrested in December that year in Rio de Janeiro while reportedly trying to obtain a permanent visa, but released after 15 months in custody when Brazil's supreme court rejected Germany's extradition request.

Early this year, Schaab hired a German lawyer to negotiate his return. Nehm said he told prosecutors he wanted to be allowed to visit his 96-year-old mother, who is terminally ill.

The two spent two hours together Thursday before Schaab was brought to a Bavarian prison, the newspaper said. He appeared in court today in Munich and was ordered held pending further proceedings.