In a speech broadcast on Hamas television on Sunday night, Hamas prime minister Ismail Haniyeh said the Palestinians had achieved a historical and strategic victory against Israel, and claimed Israel's military operation in the Gaza Strip had failed. The Hamas leader repeated the terror organization's demand for a complete Israeli withdrawal from the Strip, and for the opening of the border crossings. Haniyeh promised that Hamas would give aid to Palestinian families whose relatives were killed or injured during the war, and said Israeli leaders should be tried for war crimes. Haniyeh went on to say Hamas's decision to declare a truce on Sunday was "wise and responsible." Earlier on Sunday, hours after its leaders declared that they would continue to fight, Hamas announced a one-week cease-fire and issued an ultimatum to Israel to withdraw IDF troops from the Gaza Strip within that time. The announcement was made by Hamas officials in Syria. Later, Hamas representatives in the Gaza Strip issued a statement in which they said they would honor the cease-fire. The announcement came 12 hours after Prime Minister Ehud Olmert announced a unilateral cease-fire that went into effect at 2 a.m. on Sunday. Initially, Hamas rejected the Israeli cease-fire announcement, saying its men would continue to target IDF soldiers for as long as they remained inside the Gaza Strip and until the border crossings were reopened. Hamas's announcement that it would halt its attacks on Israel coincided with the Sharm e-Sheikh summit, which brought several Arab and EU leaders together to discuss the situation in the Gaza Strip in the aftermath of Operation Cast Lead. The announcement was seen as an attempt by Hamas to divert attention from the Sharm e-Sheikh summit and to demonstrate to the world that the movement alone held the key to calm in the Gaza Strip. Hamas officials expressed outrage over the participation of Palestinian Authority President Mahmoud Abbas in the summit even though his term in office expired earlier this month. Faraj al-Ghul, the minister of justice in the Hamas government, said that Abbas was now the former president of the PA and therefore no longer represented the Palestinians. The Hamas minister said that no Palestinian government would honor an agreement signed by Abbas after his mandate ended on January 9. He added that according to the PA Basic Law, the government of Ismail Haniyeh was the only legitimate body representing the Palestinians. The minister also called for Abbas to be brought before a Palestinian court, or any other legal forum, on charges of committing "atrocities" against the Palestinians. "We call for the arrest of Abbas so that he could be interrogated and tried for committing hundreds of atrocities and for coordinating with [US security coordinator Keith] Dayton and the Israeli occupation against the resistance," he said. "Abbas is also accused of giving a green light to the Zionist occupation to perpetrate the biggest holocaust in history against the Palestinians." The cease-fire announcement was first broadcast on Syria's state-run TV. Arab political analysts said Syrian President Bashar al-Assad was trying to show the US and the West that important decisions were taken in Damascus, not Cairo. The analysts said that the Egyptians were hoping to emerge as major players in the region by summoning Hamas representatives to Cairo and exerting heavy pressure on them to declare a cease-fire out of the Egyptian capital. Musa Abu Marzouk, the deputy chairman of the Hamas "political bureau," read a statement on behalf of his movement and several other Palestinian factions in which they announced the one-week cease-fire. "In the wake of the failure of the Zionist aggression on the Gaza Strip and its failure to impose its conditions on the resistance and our people, the Palestinian resistance groups announce a unilateral cease-fire in the Gaza Strip," the statement read. "We also emphasize our demand that the Zionist enemy withdraw from the Gaza Strip within a week and that the border crossings be reopened to allow humanitarian and relief aid to reach our people." The statement gave credit to the Syrians, Qataris and Turks for their efforts to end the fighting in the Gaza Strip, noting that the rulers of Qatar had held a summit in Doha over the weekend to discuss ways of helping the Palestinians in Gaza. Daoud Shihab, a spokesman for Islamic Jihad in the Gaza Strip, said that his group would abide by the cease-fire "out of concern for the national interests of the Palestinians and to allow humanitarian aid to be delivered to the people." Like Hamas, Islamic Jihad also declared "victory" and pointed out that Israel had failed to destroy the "resistance" or topple the Hamas government.