Hamas on Thursday called on the Palestinians to expect "surprises" during next week's rally marking the 22nd anniversary of the founding of the Islamic Movement, sparking speculation that its leaders may exploit the event to announce a prisoner exchange agreement with Israel. The rally, which is scheduled to take place at the Katiba Square in the center of Gaza City Monday afternoon, is expected to draw tens of thousands of Hamas supporters. Past events have often been used as a show of popular support for Hamas. Hamas representatives said this year's "celebration" would be different from past events because it would be held amid reports of an imminent prisoner exchange agreement with Israel. This would also be the first event of its kind since the IDF's Operation Cast Lead in the Gaza Strip. Hamas is hoping that a large turnout would refute the claim that it has lost much of its credibility and popularity among Palestinians in the aftermath of the war. A leaflet distributed by Hamas followers in the Gaza Strip on Thursday promised "fiery speeches, artist songs and hidden surprises" at next week's rally. A special committee set up by Hamas began on Thursday to decorate streets, mosques and buildings with the group's banners and flags in preparation for the rally. In some parts of the Gaza Strip, Hamas supporters launched their own celebrations by holding street marches and motorcycle tours. Khalil al-Haya, a senior Hamas official in the Gaza Strip, said that Hamas Prime Minister Ismail Haniyeh would deliver an "important" speech at the rally. Asked if Haniyeh was planning to use the event to announce that Hamas has reached an agreement with Israel over the release of IDF soldier Gilad Schalit, al-Haya said, "There will be surprises during the rally." He refused to elaborate. The Hamas official said that indirect negotiations with Israel were continuing with the hope of achieving an accord in the coming days or weeks. He also accused the Palestinian Authority leadership in the West Bank of working to sabotage any agreement between Israel and Hamas. Hamas leader Khaled Mashaal, who is currently visiting Yemen, said that Israel was to blame for the lack of progress in the secret negotiations because of its refusal to accept Hamas's demands in full. Mahmoud Zahar, the Hamas representative at the secret negotiations, said that Israel's refusal to release dozens of prisoners was hindering the signing of an agreement. He told an Egyptian newspaper that a deal was now contingent on a "political will" by both Hamas and Israel. He said that a deal could be reached soon if Prime Minister Binyamin Netanyahu accepted Hamas's demands in full. He also accused the US of seeking to obstruct a prisoner exchange agreement out of fear that such a move would bolster the movement's standing and undermine the Palestinian Authority and its leader, Mahmoud Abbas. Meanwhile, sources close to Hamas told the Kuwaiti newspaper Al-Jareeda that the main dispute between Israel and Hamas centered around eight prisoners whom Israel was refusing to include in a deal. The sources named the eight as Fatah's Marwan Barghouti, the Popular Front for the Liberation of Palestine's Ahmed Sa'dat, top Hamas operatives Ibrahim Hamed, Abbas Assayed and Abdullah Barghouti, as well as female inmates Amned Muna, Ahlam Tamimi and Qahera al-Sa'di. The sources claimed that prisoners who are serving life terms have been exerting heavy pressure on Hamas to include them in a deal out of fear that such an opportunity would not recur in the foreseeable future. Assayed, who masterminded the 2001 Netanya Park Hotel suicide bombing that killed 30 people, had even expressed his readiness to be deported to Syria in return for his release.