Hamas on Saturday rejected any possibility of declaring a unilateral truce with Israel and promised to continue firing rockets. Palestinian Authority Chairman Mahmoud Abbas, who held talks in Cairo with Hamas leader Khaled Mashaal over the weekend, failed to persuade him to declare a unilateral truce, PA officials in Ramallah said. Mashaal insisted during the talks that any cease-fire be mutual and include the West Bank, according to the officials. "Mashaal thinks that he's the leader of the Palestinians, and not President Abbas," said one official. "Mashaal is trying to undermine the new government and the president. He wants many things in return for agreeing to a cease-fire." Also Saturday, the IDF shot and killed three Palestinians who were spotted planting an explosive device next to the Gaza Strip security fence near the Kissufim Crossing. Another Palestinian was seriously wounded; the four were identified as members of Hamas's military wing. Sources in the Southern Command said that the bomb was the 60th time Palestinians tried planting bombs along the fence since a cease-fire between Israel and the Palestinians went into effect in November. At a security consultation last week, Prime Minister Ehud Olmert decided to allow the IDF to launch pinpoint strikes against Kassam rocket cells. Abbas, who met on Saturday with Egyptian President Hosni Mubarak, reiterated his call for a new cease-fire with Israel in the West Bank and the Gaza Strip. Chief PA negotiator Saeb Erekat said the Palestinians were in touch with the US and a number of European countries in a bid to reach a cease-fire with Israel. He said the Palestinians wanted a new cease-fire to be part of a wider deal that would see the lifting of financial sanctions and the removal of IDF checkpoints in the West Bank. Erekat also made it clear that a a new cease-fire should apply to the West Bank and not only to the Gaza Strip. Speaking to reporters in Cairo after meeting with Arab League Secretary-General Amr Moussa, Mashaal described the rocket attacks on Israel as self-defense on the part of Hamas. "Our people are entitled to respond to the daily atrocities perpetrated by Israel," he said. "Our people have the right to resist the occupation in the absence of a political horizon." Asked about kidnapped IDF Cpl. Gilad Schalit, Mashaal said the ball was in Israel's court. "[Prime Minister] Ehud Olmert is responsible for the delay in the prisoner exchange," he said, refusing to elaborate. Mashaal said his talks with Abbas dealt with Schalit, as well as the status of the PA unity government, growing anarchy in the Gaza Strip and ways of reconstructing the PLO to allow Hamas and other Palestinian groups to join the organization. Mashaal criticized the international community for failing to lift financial sanctions imposed on the Palestinians since Hamas took power in March 2006. He warned of a "new explosion" in the Middle East unless the international community resumed financial aid to the Palestinians. He also lashed out at the Arab and Muslim countries for failing to make good on promises to provide funds. In Gaza City, Hamas spokesman Fawzi Barhoum also emphasized his movement's "right" to fire rockets at Israel. "The Israeli enemy does not recognize the period of security calm that has prevailed over the past year," he said in response to Saturday's killing of three Palestinians by the IDF near the Gaza Strip. "All the Palestinian groups have the right to respond to Israeli massacres against our people," he said. "Why does the international community expect us to sit and watch as Israel continues its aggression against us?" Abu Mujahed, a spokesman for the Popular Resistance Committees, an alliance of a number of armed groups in the Gaza Strip, announced that his group considered the truce with Israel "dead." Commenting on the killing of the three Palestinians, who - according to the IDF - were trying to plant bombs near the border between the Gaza Strip and Israel, Abu Mujahed said: "This Israeli crime will not go unpunished. "The so-called truce with Israel has gone with the wind because of daily Israeli actions in the West Bank and the Gaza Strip." Saleh Kallab, a political analyst from the Strip, said the rocket attacks were aimed at undermining the government of Prime Minister Ismail Haniyeh and showing that Abbas was weak. He said those behind the attacks were trying to prove that important decisions regarding the Palestinians were being taken in Syria and Iran, and not in Gaza City and Ramallah. Hamas, he said, was now divided between moderates and those who oppose February's Mecca agreement, which paved the way for the Hamas-Fatah unity government. "The armed wing of Hamas is reporting to Mashaal and former [Hamas] cabinet ministers Said Siam and Mahmoud Zahar, who are all opposed to the Mecca agreement," he said. "The latest rocket attacks are aimed at embarrassing both Haniyeh and Abbas."