Shin Bet (Israel Security Agency) head Yuval Diskin and the prime minister's special envoy for prisoner exchanges, Ofer Dekel, will hold what are being called "make-or-break talks" in Cairo on Sunday in an effort to clinch a deal to free kidnapped soldier Gilad Schalit from Gaza before the Olmert government leaves office. The negotiators, who will meet with senior Egyptian intelligence officials, have until Sunday night to finalize an agreement, sources told The Jerusalem Post on Saturday night. A special cabinet session is scheduled to convene Monday morning on the exchange. Ministers will either be asked to approve the details of a prisoner swap, or be briefed on the unsuccessful efforts. Fourteen of the 26 cabinet ministers have told the Post that they would likely support a deal, or at the very least would not prevent it from going forward. Prime Minister-designate Binyamin Netanyahu has been updated by Olmert, but was not asked to approve the latest developments. Israel's deadline of Sunday night for an agreement is based on the expectation that coalition agreements for the new government are to be presented to the Knesset on Tuesday. "This is the last week that decision-makers have to fulfill their obligation to save Gilad," Yoel Schalit, Gilad's older brother, told Channel 2 on Saturday. Dekel returned to Israel from his latest round of talks with Egyptian mediators on Thursday and briefed Prime Minister Ehud Olmert. The fact that Dekel was ordered to return to Cairo yesterday, accompanied by Diskin, is a sign that progress was achieved, although officials in Jerusalem refused to talk of a "breakthrough." Although officials remain tight-lipped on details of the contacts with Hamas, via Egyptian mediators, it is believed that a figure of 450 Palestinian prisoners in return for Schalit's release was agreed to some time ago. What is believed to be holding up a deal is Israel's refusal to free an unspecified number of detainees demanded by Hamas, and Jerusalem's insistence that some of the West Bank prisoners be exiled either to Gaza or abroad. Hamas has denied that any deal is taking place. This latest round of talks in Cairo comes after Schalit's family stepped up its campaign to pressure Olmert to finalize a deal before he leaves office. For the past week, Gilad's parents Noam and Aviva have sat in a tent they pitched outside the prime minister's Jerusalem residence. They even held a Friday night dinner there and intend to stay in the tent until Olmert leaves office. Numerous ministers, politicians and visitors from abroad have stopped by the tent to show their support for the Schalit family. At least 10,000 of those visitors signed a petition in which they urged the government to authorize a prisoner swap for Gilad. On Friday, Yoel Schalit, who has been largely absent from public protests for his brother, joined his parents in the tent, and on Saturday he conducted a number of television interviews. "This is a critical week and a critical period. We hope that this campaign, and the tent and the wide public support, will push the decision-makers to make the right step to return Gilad," he said. When thinking of his brother, Yoel said, he has tried to imagine the suffering and pain of 993 days of captivity. Should his brother be released, Yoel said, "We do not know what he has gone through and how he will be. We hope he will return healthy. I believe he is strong enough to endure what he needs to, and we will give him the support he needs, but first he has to return." His father was more cautious when speaking with the media. Noam Schalit refused to ride the wave of optimism generated by the latest efforts to release his son. "I'm not a prophet," he said, when asked about Diskin and Dekel's Cairo talks on Sunday. Since his son was taken, he said, there had been so much frustration and hope. "We are always taking one step forward and another step backwards." Now, he said, "we are waiting." On Sunday morning, Noam Schalit will be joined in the tent by Transportation Minister Shaul Mofaz. Among those who have voiced their support for the Schalit campaign are a group of 20 reservists who on Thursday wrote a letter to the prime minister and urged him to free Gilad. They said that many of them had served in Operation Cast Lead, and that they have since watched how their achievements there had disappeared. If Schalit is not freed, the reservists said, they feared that his fate could be like that of missing airman Ron Arad, who was kidnapped in Lebanon after his plane crashed there in October 1986. He disappeared in May 1988. There is no price that is too high, the reservists said, to pay to return a soldier who was kidnapped while serving his country. "We call on you to finish this mission and to leave a clean table," they wrote.