The tight secrecy over the police investigation into Prime Minister Ehud Olmert is set to continue, police said Monday evening, amid media reports that a significant development in the case will take place Tuesday. Police spokesman Mickey Rosenfeld denied claims aired on Monday on Army Radio of an impending ease of the media ban, saying, "The investigation is proceeding as normal. I am not aware of any changes soon [to the media ban]." A spokesman for Police Insp.-Gen. David Cohen also denied knowledge of any lifting of the gag order, adding that "things are very sensitive." Earlier on Monday, Army Radio cited unnamed sources who claimed that sections of the ban would be lifted "in the next 24 hours, following major progress expected in the investigation." The officials were quoted as saying that the investigation's findings at this stage are "reliable" and "will shock the country" when revealed. Earlier, the Justice Ministry and police released a statement citing "exceptional circumstances" as being behind the urgent police investigation into Olmert. The letter addressed the mounting calls for the across-the-board media ban to be lifted. While vowing to release details of the case as soon they could, the Justice Ministry officials and police failed to commit to a specific disclosure date. "We are well aware of the public interest and need to receive information," the letter, signed by the Justice Ministry spokesman Moshe Cohen, said. "Indeed, the situation in which the reigning prime minister is interrogated under caution, while no information, general lines of inquiry, or the substance of the suspicions against him are released creates difficulties for the public, as well as legal-constitutional challenges," the letter continued. "At the same timeâ€¦ there is a vital public interest not to thwart the investigation and not to harm chances of discovering the truth." The officials promised "to closely monitor the situationâ€¦ with a view to allow, as early as possible, the release of information to the public." In the first meeting of the Knesset plenum since the latest investigation into the prime minister was revealed last week, Olmert's political rivals from the Likud were quick to capitalize on the latest scandal to cast aspersions on the government's diplomatic attempts. "It is inconceivable that from investigation to investigation Olmert continues with negotiations about concessions," said the Likud faction chairman Gideon Sa'ar. "Between investigations, don't touch the lands of Judea and Samaria. Don't you dare to place a hand on Jerusalem. It isn't one of your apartments up for sale. Don't pass on secret messages to [Syrian President Bashar] Assad that Israel is ready to leave the Golan Heights because it is not true. You don't have a majority in the house to continue your process of unilateral concessions." MK Binyamin Netanyahu (Likud) took a similar tack when he addressed Olmert's police woes on the floor of the Knesset, interrupting a speech made by Absorption Minister Yaakov Edri (Kadima). "Is it ethical that Olmert is carrying out negotiations with the Palestinians while he is under investigation?" Netanyahu called out. Edri sprang to his boss's defense, arguing that "there were prime ministers who were under investigation. It is regrettable, but they carried out negotiations. Olmert is dealing with the most sensitive topics, and who like you - Bibi Netanyahu - understands that." Later in the day, Sa'ar went a step further and after news was leaked of progress in negotiations with the Palestinians Monday evening, the faction chairman accused Olmert of manipulating the negotiations to preserve his own political career. "As long as the criminal investigations against Olmert increase and progress, Olmert speeds up the process of unilateral concessions and giving away of Israel's strategic assets," he said, calling on Shas to "immediately pull out of the government before additional - and possibly irreversible - damage is caused to Israel and to Israel's future." Meanwhile, President Shimon Peres pointed out Monday that Prime Minister Ehud Olmert has not been accused of anything. Speaking at a media conference at Beit Hanassi with the Foreign Press Association, the president said that as far as he was concerned, Olmert remains innocent until charges are brought against him and he is tried and convicted in a court of law. Democratically, it was perfectly in order for the police to question Olmert, said Peres. "Personally, I don't know anything that would change my attitude regarding the prime minister," Peres said. Greer Fay Cashman contributed to this report.