US President George W. Bush tried Wednesday to reassure Israelis worried about the US commitment to keeping Iran from obtaining nuclear weapons. "Iran is an existential threat to peace," Bush told Prime Minister Ehud Olmert at the outset of talks at the White House. "It's very important for the world to take the Iranian threat quite seriously, which the United States does." Bush said they also would discuss Syria's influence in Lebanon and the government's attempts to negotiate peace with the Palestinians. As they spoke, Palestinian Authority President Mahmoud Abbas called for a new dialogue with Hamas. Abbas said he will call for new legislative and presidential elections if the talks succeed.