Israel began pulling troops out of the Gaza Strip Sunday as a fragile truce came into effect after its deadliest offensive ever on the battered Palestinian territory. As medics scrambled to pull dozens of bodies from the mountains of rubble left by Israel's three-week offensive, Hamas said it would hold fire for one week to allow Israeli troops to withdraw. European and Arab leaders meeting in Egypt ratcheted up calls for an Israeli withdrawal from the Gaza Strip and announced plans for an international aid conference. The leaders, as well as UN Secretary General Ban Ki-moon and including Palestinian President Mahmoud Abbas, also issued a rallying call to the world to support the fragile truce between Israel and Hamas. Israeli Prime Minister Ehud Olmert later told the European leaders at a joint press conference in occupied Jerusalem that he wanted to pull his troops out “as quickly as possible.” British Prime Minister Gordon Brown said this should be just the start of a concerted international effort to stabilise the region. “This fragile ceasefire has got to be followed immediately, if it is to be sustainable, by humanitarian access... by troop withdrawals, by an end to arms trafficking,” he told journalists in Sharm el-Sheikh. “Today a humanitarian tragedy must be met not just by sympathy but by an immediate mobilisation of aid.” Amid calls for a massive humanitarian effort to be launched to take advantage of the ceasefire, Mubarak announced that Egypt planned to host an international aid conference, although he did not say when. German Chancellor Angela Merkel called the halt in fighting a “window of opportunity” in terms of achieving a “lasting peace” between Israel and the Palestinians. Meanwhile, Middle East Quartet envoy Tony Blair said Sunday that an Arab initiative for peace in the region was “not dead” despite Israel's lethal 22-day war on the Gaza Strip. “The Arab peace initiative is not dead unless we make it so,” Blair said in Riyadh.