Hamas denied Sunday that it had reached understandings with Israel over a truce or period of calm, but confirmed that Egypt was playing a role in trying to achieve a cease-fire. Palestinian Authority officials in Ramallah told The Jerusalem Post that Hamas and Israel had reached "secret understandings" to stop the violence. The officials claimed that the latest agreement was reached under the auspices of the Egyptians and that Hamas had pledged to stop firing rockets at Israel. Israeli officials emphatically denied that it was negotiating any type of cease-fire with Hamas, or through a third party. "Hamas's position regarding a tahdiyah [calm] has not changed," said Muhammed Nasr, a senior Hamas official in the Gaza Strip. "Any tahdiyah must be mutual and comprehensive." He said the Egyptian government was making huge efforts to reach a deal that would be acceptable to all parties. "Egypt has been working to achieve calm for several years now," he added. "In 2005 the Egyptians succeeded in achieving a truce between the Palestinian factions and Israel." Nasr said that Hamas was prepared for a truce with Israel, but would not agree to a unilateral one. "In the past, we announced a unilateral truce, but Israel continued to launch attacks on us," he said. "This time we won't repeat the mistake of the past and that's why we want any truce to come from both sides and to be implemented simultaneously." The Hamas official said his movement was also demanding that any truce include the West Bank, and not only the Gaza Strip. "If Israel is serious about a truce or tahdiyah, it must accept our demands," he said, adding that Hamas was also asking that Israel lift the blockade imposed on the Gaza Strip and reopen all border crossings there. Meanwhile, Hamas and Fatah have agreed to resume talks over ending their differences, representatives of the two parties said. Officials from Fatah and Hamas are scheduled to hold talks in Yemen in the coming days in yet another attempt to end the power struggle that has been raging in the Palestinian territories in the past two years. Yemeni President Ali Abdullah Saleh invited the two parties to the talks after launching an initiative aimed at ending the power struggle. The initiative calls for ending Hamas's control over the Gaza Strip and holding early elections in the West Bank and Gaza Strip. Yasser Abed Rabbo, a senior PLO official and a close aide to Abbas, on Sunday accused Prime Minister Ehud Olmert of seeking to undermine the PA. He stressed that the PA would not resume the talks with Israel until it agreed to a cease-fire. In response to Olmert's remarks to the effect that the PA was not doing enough to fight terrorism, Abed Rabbo said: "How can any government fulfill its duties when the West Bank is under [Israeli] siege and there are hundreds of Israeli checkpoints and while settlement construction is continuing, particularly in Jerusalem?" Abed Rabbo added that Israel was deliberately undermining the PA by launching daily incursions into Palestinian cities in the West Bank, especially where the PA security forces had succeeded in restoring law and order. "Both Israel and Hamas are taking turns in weakening the PA," he said. "Their goal is to increase tensions and violence. They want to separate the West Bank from the Gaza Strip so that the Palestinians would not be able to establish a state. Both Hamas and Israel have a common interest in undermining the PA." Hamas also appealed to Abbas not to return to the negotiating table with Israel, saying such a move would be a "crime" against the Palestinians. "We call on the Ramallah leadership to stay away from the talks with the Israeli enemy," said Hamas spokesman Sami Abu Zuhri. "We don't understand how Abbas can resume the talks after all the massacres that Israel perpetrated in the Gaza Strip." Abu Zuhri added that Hamas found it strange that Abbas was prepared to resume talks with Israel while continuing to oppose any form of dialogue with Hamas. Yahya Musa, another top Hamas official in the Gaza Strip, accused Abbas of lying when he said that he would not resume talks with Israel before a cease-fire is reached between the Palestinians and Israel. "Abbas is tampering with the feelings of the Palestinian people," he charged. "We have become accustomed to this man's lies and there's nothing new in what he says or does." Musa claimed that Abbas had actually never suspended the talks with Israel."Resuming the talks after the death of more than 130 Palestinians in the Gaza Strip is a big sin," he said. "Abbas's forces, which operate on instructions from the Israeli occupation, are continuing to coordinate with Israel on security matters."