Hamas toughened its stance during Egyptian-mediated negotiations for Gilad Schalit's release, went back on understandings that were agreed upon during the past year and raised extreme demands, the Prime Minister's Office said in a statement released late Monday night, following the return of Shin Bet (Israel Security Agency) head Yuval Diskin and senior negotiator Ofer Dekel from marathon talks in Cairo over the kidnapped soldier. The statement said further that the Islamic group adopted its new, tougher position despite generous offers which Israel presented in the latest round of talks. The brief assessment came after a day of negotiations in Cairo, where Egyptian mediators attempted to help iron out the differences between Israel and Hamas in order to bring about a prisoner swap. While reports were mixed throughout the day about the chances of a deal, the latest statement casts a shadow over the last-ditch efforts. Diskin and Dekel began briefing Prime Minister Ehud Olmert on the talks at 9:30 p.m., at the Kirya defense complex in Tel Aviv. On Tuesday, the cabinet will receive updates on the matter, and a decision is expected to follow on whether to send the negotiators back to Cairo for another round of talks, or whether the gaps are too wide to bridge and the issue, therefore, should be left to the next government. Meanwhile, IDF Chief of General Staff Lt.-Gen. Gabi Ashkenazi cut short his trip to the US, where he was due to speak at a Friends of the IDF event, to attend the cabinet meeting. According to the various accounts Monday night, Israel had agreed to release most of the prisoners on the Hamas list, with Channel 2 reporting 400 out of the 450, and the main point of contention was Israel's demand to expel several of the prisoners to foreign countries. Hamas claims about the status of talks ranged from reserved to optimistic on Monday. "Israel has agreed to free all the prisoners on the updated list," read a statement on the Web site of Hamas' military wing, also claiming that the only point of disagreement was Israel's demand to deport several of the prisoners. Hamas emphasized that the progress was the most significant made so far and Channel 2 cited the group's officials as saying that the talks had been conducted in a good atmosphere. The television channel also said Monday night that Hamas had insisted that its officials should not further discuss the details of the talks. Another Hamas official reportedly told CNN that "99.99 percent" of the issues on the matter had been solved. Meanwhile, Defense Minister Ehud Barak spoke of the ongoing Schalit negotiations at Monday's Labor faction meeting. "I want to give strength to the envoys in Cairo who are making the utmost efforts to bring an end to Gilad Schalit's captivity and I wish them success," he said. Earlier Monday, outgoing Pensioners Affairs Minister Rafi Eitan said that he believed Diskin and Dekel would return from Cairo with a recommendation for a deal to release Schalit. Speaking to Army Radio from the Schalit protest tent outside the Prime Minister's Residence in Jerusalem, Eitan said, "I believe that the results of the talks will be positive." He declined, however, to detail the basis for his evaluation. The minister added that he would vote in support of a deal to free the captured soldier. The soldier's parents, Noam and Aviva Schalit, set up the tent in the capital last week, in an effort to pressure Olmert to make a deal before he leaves office. Since then, they have been joined by thousands of supporters, including politicians and cabinet ministers. On Sunday, just after midnight, Olmert had postponed Monday morning's special cabinet session on Schalit by 24 hours, in order to allow Diskin and Dekel to spend an extra day in Cairo to hammer out a prisoner exchange deal. "It should be emphasized that as of yet, there is no sign that indicates a result in any particular direction in the negotiations," the Prime Minister's Office had said. Diskin and Dekel had been expected back early Monday to report to Olmert on whether a breakthrough had been achieved, but at the last moment they decided to spend an extra day in Egypt. According to the London-based daily Al-Hayat, Ahmad Jabari, the commander of Hamas's Izzadin Kassam Brigades was also in Egypt for the talks. The paper quoted Palestinian sources as saying that Jabari arrived in Cairo four days ago to act as the head of the Hamas negotiating team on the Schalit issue. The Jerusalem Post could not confirm the report. Dekel's trip, which followed talks in the Egyptian capital last week, fueled speculation that there was still a chance for a deal before Prime Minister-designate Binyamin Netanyahu forms a government, possibly by the end of the week. Netanyahu kept silent on the issue Sunday, saying he would end his long-standing policy of not commenting on Schalit's fate only after he forms a government, which he intends to do by Thursday's deadline. "When he is prime minister, he will speak about the issue," a senior source close to the Likud leader said. "But right now there is nothing positive that can come in any direction from making any comments." On Tuesday, after Dekel and Diskin return, Olmert plans to brief Gilad's parents about the latest round of talks, after which he is scheduled to convene the cabinet. Ministers will either be asked to approve the details of a prisoner swap, or be briefed on the failure to strike a deal before Olmert steps down. "The government will convene to discuss the outcome of the talks, and according to the circumstances, we will decide if and how we will make a decision," Olmert told the cabinet on Sunday, at its regular weekly meeting. Already more than half the ministers have said they are likely to support such a deal, including Interior Minister Meir Sheetrit, Transportation Minister Shaul Mofaz and Welfare and Social Services Minister Isaac Herzog. "I have said in the past, and I repeat: We want to bring Gilad home, and we are making great and unprecedented efforts to do so," Olmert said. Part of the problem, he explained, was that Hamas was "an inhumane terrorist organization that believes human compassion is a weakness." During the various phases of the drawn-out negotiations, Hamas has asked for the release of as many as 1,400 security prisoners, including 450 believed to have been involved in terrorist attacks that killed Israelis. The government had initially balked at the release of the 450, but some media reports said it had now ceded this point.