WASHINGTON (AFP) - The United States said Friday it was working towards a ceasefire that permanently prevents Hamas from resuming rocket attacks on Israel, as calls mounted worldwide for Israel to halt its week-long siege. After briefing President George W Bush on events 18 days before he hands the White House to his successor Barack Obama, Secretary of State Condoleezza Rice also said she had no plans at the moment to travel to the Middle East. "We are working towards a ceasefire that would not allow a re-establishment of the status quo ante where Hamas can continue to launch rockets out of Gaza," Rice said. "It is obvious that that ceasefire should take place as soon as possible, but we need a ceasefire that is durable and sustainable." On Wednesday the White House backed Israel's refusal to cease its assault on Gaza, saying Bush and Israeli Prime Minister Ehud Olmert were "on the same page." The Islamist movement Hamas must agree to stop firing rockets into Israel now and in the future before any potential ceasefire to the Gaza violence, White House deputy press secretary Gordon Johndroe said.