Senior law-enforcement officials said over the weekend that a new criminal investigation against Prime Minister Ehud Olmert is so "severe" that he will have to leave his post. But the Prime Minister's Office rejected this assertion, and the Attorney-General's Office said the possibility of suspending Olmert had not been discussed at all. In the opposition, however, calls mounted on Olmert to step down pending the result of the mysterious probe, whose details have been barred for publication by a court gag order. MK Silvan Shalom (Likud) said he was working to dissolve the Knesset when it opens its summer session in two weeks, saying "the government of Ehud Olmert has reached the end of its road." In an unusually expedited procedure, Olmert was questioned under caution at his official residence by members of the National Fraud Unit for about 90 minutes on Friday morning over what police would only say were new suspicions against him. A top law enforcement official was quoted by Channel 1 as saying on Friday that Olmert's tenure was now in danger due to the severity of the latest investigation. The official expressed doubts over Olmert's chances of staying on as prime minister. But officials in the Prime Minister's Office said they were confident the new suspicions would prove to be unfounded, adding that Olmert "answered all questions put to him by investigators, as he had on all previous occasions." A police spokesman poured cold water on a Channel 2 report aired Saturday night that claimed Olmert would be questioned again, noting that similar reports of impending questioning by police of the prime minister in the past had often turned out to be inaccurate. "There is no change in the status of the investigation since Friday," the spokesman added. "In the meantime, investigators are working on the case." Meanwhile, the Justice Ministry issued a statement on Friday saying that the police had questioned Olmert regarding allegations that had not been investigated until now. Before Friday's interrogation, Olmert was already under investigation regarding allegations of corruption regarding four separate cases. Publication of details of the new investigation are barred by a sweeping, court-imposed media blackout. Police Fraud Unit head Lt.-Cmdr. Shlomi Ayalon and two detectives arrived at Olmert's residence at 10 a.m. on Friday and questioned him. Earlier, police had received a special permit to interrogate Olmert within 48 hours from Attorney-General Menahem Mazuz. Some commentators have speculated that Mazuz issued the permit in response to concerns that Olmert might try to coordinate his testimony with his bureau chief, Shula Zaken, who has been his secretary for 30 years. Zaken was also interrogated recently over possible links to the case at the National Fraud Unit's offices in Bat Yam. "The prime minister answered all of the investigators' questions on the subject and will continue to cooperate with all legal authorities to the extent he is required to do so," the Prime Minister's Office said in a statement on Friday. It added that Olmert "is convinced that with the discovery of the truth in the police investigation, the suspicions against him will dissipate." Labor MK Shelly Yacimovich, a member of Olmert's coalition, called the scope of charges against Olmert "unprecedented," and said he should suspend himself immediately. "It has been proven beyond any doubt that the prime minister can't be under serial investigations and also lead the country," she told Israel Radio. "Olmert is stuck up to his neck in investigations. We cannot have a prime minister who is serially investigated by police. He is plainly corrupt even without waiting for a conviction." "In the entire world there was never yet a precedent of a prime minister against whom so many investigations were held," Yacimovich added. Meretz MK Zehava Gal-On echoed Yacimovich's comments, saying that Olmert should step down until the investigation was complete. It was clear that Olmert did not know how to take personal responsibility and that Mazuz should "show him the way" and advise him to suspend himself, Gal-On said. Likud MK Gideon Sa'ar called on the Labor Party to withdraw from the Olmert-led government of "serial suspects." Labor MK and former cabinet minister Ophir Paz-Pines urged Mazuz to promptly publicize the apparently new allegations against Olmert. Paz-Pines told Israel Radio that if they were indeed so severe that they lead to an indictment, Olmert could not possibly continue to serve as prime minister, "even for one more day." "Mazuz needs to immediately tell the public what is going on. If there is proof, concrete allegations, and if the accusations are of bribery and taking money, there isn't a more severe offense for a pubic servant, especially for a prime minister," Paz-Pines added. In Kadima, MK Yoel Hasson came to Olmert's defense. "From past experience, we know that all the investigations started with a lot of noise and ended with nothing," he said. "The political system should not get hysterical and take rash political actions that will unsettle the government." Mazuz has ordered two criminal investigations into suspicions that Olmert acted improperly while he was industry and trade minister. He is also suspected of improprieties in the purchase of a house in Jerusalem. In November, police recommended closing another case involving allegations that he tried to steer sale of the government's controlling stake in Bank Leumi in the direction of supporters. However, the new state attorney, Moshe Lador, has not decided whether to close the file.