A German judge ordered John Demjanjuk to appear in court on Monday for his trial over allegations that he was a guard at the Nazis' Sobibor death camp, despite the 90-year-old's complaints about health problems.The former Ohio autoworker was informed Monday morning that he was being ordered to attend the trial, presiding judge Ralph Alt said. This is the second time the judge has ordered Demjanjuk to attend, since the trial opened last November.Defense attorney Ulrich Busch protested the decision, saying his client was not fit to follow the hearing and could barely hear what was being said in court. For most of his trial, Demjanjuk has followed the hearings from a bed in the courtroom and showed no reaction to the proceedings.Court doctor Albert Stein said Demjanjuk complained about having a very strong headache, but answered his questions "clearly and energetically".Demjanjuk, who was deported from the U.S. to Germany in May 2009, suffers several medical problems, but was declared fit to face trial.He is being tried on 28,060 counts of accessory to murder — charges that he denies. The defense maintains Demjanjuk was a Soviet soldier captured by the Germans and spent most of the war in prison camps himself.Busch said the defendant is also suffering pain because the bad suspension of the ambulance taking him to court.But Judge Alt said: "I don't see a reason to declare him unfit for trial."Demjanjuk followed the Monday session lying in blue pajamas on a stretcher, wearing sunglasses and showing no reaction to the proceedings.The hearing was adjourned after only 20 minutes. In the afternoon, Busch will continue cross-examining a U.S. historian, Bruce W. Menning, who last week questioned Demjanjuk's account of his whereabouts in the final years of World War II.Since the start of the trial, about a dozen sessions have been canceled due to Demjanjuk's health issues.The Ukrainian-born Demjanjuk had his U.S. citizenship revoked in 1981 after the U.S. Justice Department alleged he hid his past as the notorious Treblinka guard "Ivan the Terrible." He was extradited to Israel, where he was found guilty and sentenced to death in 1988, only to have the conviction overturned five years later as a case of mistaken identity.