Despite the imminent truce between Israel and Hamas in the Gaza Strip, security officials said Tuesday that there was concern that other Palestinian terror factions such as Islamic Jihad or the Army of Islam would try to sabotage the deal by perpetrating a major attack that would force Israel to respond. Defense Minister Ehud Barak reiterated his support for a truce with Hamas but stressed that the IDF was prepared for all developments. The IDF's top brass on Tuesday expressed skepticism regarding the chances that the cease-fire will last. "We are giving a chance to the cease-fire, but we are preparing for action," IDF Chief-of-Staff Lt.-Gen. Gabi Ashkenazi said during a meeting of the Knesset's Foreign Affairs and Defense Committee. Brig.-Gen. Yossi Baiditz, head of Military Intelligence's Research Division, said that the IDF had already prepared and presented plans for operations in Gaza should the truce collapse. MKs, he said, had already been briefed on the various options and contingencies. "Even if the calm is achieved with Hamas and the other terror organizations, it will be temporary and breakable," he added. An official in the Prime Minister's Office said Israel would judge the cease-fire by actions on the ground, and not statements. "If we face a situation where every few days Islamic Jihad or other terrorist organizations fire rockets, then this cease-fire will be short lived," he said. Hamas officials expressed deep satisfaction with the agreement, saying it showed that Israel had finally accepted Hamas's conditions. One official told The Jerusalem Post that "if Israel abides by the agreement, [kidnapped IDF soldier] Gilad Schalit could be home soon." He said Hamas presented the Egyptians with a list of 350 Palestinian prisoners whom it wants in return for Schalit. "The Egyptians have told us that Israel has agreed to release most of those appearing on our list," the Hamas official said, adding that the most significant achievement for Hamas was that Israel would no longer be involved in what happens at the Rafah border crossing. "We have reached understandings according to which Israel would have no role in running the Rafah border crossing," he said. "From now on, the border would be managed by Palestinians, Europeans and Egyptians." Another Hamas official said the fact that his movement managed to separate the case of Schalit from the cease-fire agreement was also a "major victory." He added that it was now clear that the Rafah border crossing would be reopened before the release of Schalit. "In the past, Israel was opposed to the reopening of the border crossings unless the soldier was released," he noted. Hamas legislator Marwan Abu Ras said the cease-fire agreement also calls for the release of dozens of Hamas members from Egyptian jails. He said the Egyptians have so far agreed to release Ismail Matar, one of the commanders of Hamas's armed wing, Izaddin Kassam, who has been in prison for four years. Abu Ras expressed "astonishment" at the continued detention of scores of Hamas members in Egyptian jails. "How is it possible for Egypt to mediate a prisoner exchange between us and Israel while many of our young men are being held in Egyptian prisons?" he asked. "Why are they being held? How are they a threat to Egypt's national security?" In Gaza, Hamas confirmed that it had reached a cease-fire with Israel meant to halt a violent cycle of Palestinian rocket attacks that have killed seven Israelis over the past year and Israeli reprisals that have killed more than 400 Palestinians. However, Hamas said it would respond to "any Zionist aggression." Gaza Hamas leader Mahmoud Zahar said all the armed factions in Gaza were on board with the truce. Speaking after another Hamas official outlined details of the truce at a news conference in Gaza City, Zahar said Hamas would not put down its weapons, because he did not believe Israel would implement the cease-fire. "We don't trust them, but let's see," he said. Rebecca Anna Stoil, jpost.com staff and AP contributed to this report.