VIENNA, Austria (AP) _ The trial of an aging doctor accused in the deaths of nine children in a Nazi-run euthanasia clinic was suspended indefinitely today after a psychiatrist testified the defendant was suffering from increased dementia.

Dr. Heinrich Gross, 84, went on trial today in a Vienna court for the third time in a case stemming from the deaths of thousands of children killed by the Nazis because they did not fit Adolf Hitler's vision of a perfect world.

About a half hour into the session, the judge, Karlheinz Seewald, suspended the proceedings indefinitely after a court-appointed psychiatrist, Dr. Heinrich Haller, testified that Gross' dementia had worsened since two previous examinations in 1998.

Seewald ordered further tests over the next six months, leaving open the possibility the trial could resume. Based on the psychiatrist's testimony, however, it appeared unlikely that Gross would ever stand trial.

Gross, who attended the session, shook hands with supporters after the proceedings were halted.

The defendant was put on trial twice before, but the case was thrown out in 1950 because of legal technicalities and again in the 1980s because the 30-year statute of limitations on manslaughter had expired.

Prosecutors, however, filed a new set of charges, accusing him of complicity to murder in the cases of nine children who allegedly died as a result of abuse.

Gross has pleaded innocent. ``I was always against euthanasia,'' he told the weekly magazine News. ``I never sped up anyone's death, nor did I assign anyone to do so.''

Gross' lawyer, Nicolaus Lehner, said his client was at the war front during the time the nine children were killed. Lehner also has argued that his client was responsible only for initial examinations of children admitted to the clinic.

``If a child dies after being admitted to an institution, it is not the fault of the doctor administering the admission examinations,'' Lehner said.

Lehner has called the trial a politically motivated ``scandal'' at a time when Austria's Nazi past is under intense scrutiny. Austria's new government includes a far-right party whose leader, Joerg Haider, has praised the Hitler era.

Prospective witnesses included a survivor of the clinic, Johann Gross, who is not related to the defendant. Before the trial, Johann Gross said he did not see the defendant kill anyone. But other memories of abuse are vivid.

``I would crawl on my hands, dragging my legs behind me because they were devoid of sensation,'' Gross said, recalling injections he said were given by the defendant as punishment for trying to escape the institution. ``Or I would throw up, again and again.''

Some infants were left on hospital balconies naked or lightly dressed overnight during winter, said Johann Gross.

``The balconies were only 30 or 40 (yards) from our dormitory,'' he recalled. ``I heard them whimpering _ and then I heard the parents got a letter saying their child had died of pneumonia.''

Other children were killed by injection, medical experimentation, or simply starved. The Nazis called them ``unworthy lives.'' Across Europe, 75,000 people, including 5,000 children, were murdered for being mentally or physically handicapped.

Fear during Hitler's rule and shame afterward stifled discussion of Austria's Nazi past until the 1980s _ and permitted defendant Gross and others to evade responsibility for alleged crimes during that era.

Basing his research on the preserved brains of children killed by the Nazis, Heinrich Gross subsequently published nearly a dozen articles by 1966. A prominent postwar neurologist and recipient of a high state award, he served as an expert witness in hundreds of court cases up to the mid-1980s.