Israel reopened the Erez, Sufa and Nahal Oz crossings into Gaza on Sunday morning, after they were shut down Thursday in response to a Kassam rocket attack. Meanwhile, Israel warned Saturday that any delay by Hamas on contacts over a prisoner swap involving the release of captured soldier Gilad Schalit may torpedo the Egyptian-mediated Gaza Strip truce agreement reached last month. The warning followed an announcement by Hamas on Friday that it was considering suspending talks over the release of Schalit because Israel was not abiding by the cease-fire. But an Israeli official told The Jerusalem Post that Hamas was already violating the terms of the truce by permitting sporadic hostile fire from Gaza into Israel and violating the Schalit clause could torpedo the whole deal. "Under the terms of the truce, Hamas is committed to expediting activity aimed at bringing about the release of Gilad Schalit," the official said. "If this element is violated as well it will lead Israel to seriously question the continuation of the agreement." The Hamas threat to freeze contacts on a prisoner swap came despite statements issued by other leaders of the organization to the effect that the indirect talks with Israel over Schalit's fate would begin soon in Cairo. The contradictory statements are seen as yet another sign of divisions among the Hamas leadership as to how to deal with the case of Schalit. Hamas leaders in Syria have toughened their stance regarding Schalit because they believe that Israel is prepared to release a larger number of Palestinian prisoners. Hamas representatives in the Gaza Strip, on the other hand, are eager to end the case of Schalit as soon as possible and are even said to be prepared to make concessions in this regard. Musa Abu Marzouk, the Damascus-based deputy head of the political bureau of Hamas, told the London-based Al-Hayat daily that Hamas would not send a delegation to Cairo. "It does not make any sense that we should begin negotiations while Israel does not honor the truce," he said. "The case of Schalit will be postponed until the Egyptians make a bigger effort to force Israel to honor the agreement, open the border crossings and prevent Muhammad Dahlan and Fatah from pursuing their attempts to sabotage the truce." However, Hamas spokesman Fawzi Barhoum said he expected Egypt to issue invitations to launch negotiations in Cairo over a prisoner exchange in the coming days. He said Hamas would accept the invitation despite its reservations about the cease-fire agreement that was reached two weeks ago. "The Egyptians are about to issue invitations for indirect talks between Israel and Hamas," he said. "We want to conclude the case of Schalit after guaranteeing the success of the truce." Barhoum accused Israel of failing to fulfill its pledge to reopen the border crossings in the aftermath of the truce agreement. "Israel has not abided by the agreement," he charged. "Israel is continuing to act as if it's alone in this conflict." He added that Hamas had made it clear to the Egyptians that it was opposed to beginning talks over the fate of Schalit before ascertaining that Israel was honoring the cease-fire agreement. Hamas leader Mahmoud Zahar denied reports about tensions between his movement and Egypt. The reports, which appeared in a number of Arab newspapers, claimed that Hamas was seeking to cancel Egypt's role as the major mediator with Israel. According to the reports, Hamas leaders accused the Egyptians of endorsing Israel's stance in the indirect negotiations with Israel. But Zahar said Saturday that Hamas continues to trust the Egyptians. "The Egyptians are not putting any pressure on Hamas," he said. "They have never put any pressure on us. In fact, the Egyptians have endorsed our position and they have always been on our side."