A Hamas delegation headed by Mahmoud Zahar returned to the Gaza Strip over the weekend after holding talks in Cairo and Syria on a possible prisoner agreement exchange with Israel. Hamas legislator Salah Bardaweel cautioned against "excessive optimism," saying only limited progress has been achieved so far. The Islamist movement's leader, Damascus-based Khaled Mashaal, is scheduled to travel to Cairo late this week for additional talks on the case of kidnapped IDF soldier St.-Sgt. Gilad Schalit. On Friday, Mashaal arrived in Amman to attend the funeral of his 91-year-old father, who died last week. Mashaal was expelled from Jordan and the Hamas offices in the kingdom were closed down 10 years ago. Jordan's King Abdullah II gave Mashaal permission to visit the kingdom for only 48 hours to attend the funeral. He was barred from talking to reporters or making public statements during his stay in the kingdom. The Hamas delegation that returned to Gaza had met in Cairo with German security officials who were mediating between the Islamist movement and Israel, a Hamas representative in the Strip said on Saturday. In addition to Zahar, the delegation included Sharif Farwaneh, Issam Rabah al-Mamlouk and Muhammad Khaled Zahar. Germany's BND foreign intelligence service was actively involved in negotiations for the release of Schalit, Der Spiegel reported on Saturday evening. The BND's proposal includes Israel first releasing at least 450 Palestinian prisoners in exchange for Schalit. After his release, the Israeli government has expressed a willingness to release further prisoners. The government has insisted that the prisoner releases be done as a humanitarian gesture and without any time pressure, Der Spiegel reported. Hamas has been given until the beginning of September to respond to the proposal. The German negotiator has been activated at the request of the Israeli government and has been commuting since mid-July to conduct negotiations with the parties to the conflict, according to the report. Asked to comment on reports in Arab media outlets about a breakthrough in the negotiations, Bardaweel said: "It's premature to talk about a deal. The German mediators are still in the process of gathering information." Bardaweel said that reports to the effect that a deal was imminent were aimed at exerting pressure on Hamas regarding the case of Schalit. He added that the ball was still in the Israeli court and that if Israel really wanted to reach a deal, it could do so quickly by accepting the demands of Schalit's captors. Bardaweel said that despite the involvement of German mediators in the negotiations, the Egyptians were continuing to play a role to bridge the gap between Hamas and Israel. Sources close to Hamas said that Ahmed Ja'bari, commander of Izzadin Kassam, the movement's armed wing, was still in Cairo for talks with Egyptian General Intelligence officials about the prospects of reaching a deal with Israel. Ja'bari, the sources said, was one of the few Hamas operatives who were in direct contact with Schalit's captors. The sources added that Hamas had agreed to the deportation of 120 Palestinian security prisoners who were supposed to be released by Israel in the framework of a prisoner swap. The prisoners are among some 450 inmates who are serving lengthy sentences and who are included in the list provided by Hamas to the Egyptians and Germans. Altogether, Hamas was demanding the release of about 1,000 prisoners in return for Schalit, the sources said.