Attacks that killed 172 people in Mumbai in November could happen in the United States, FBI Director Robert Mueller warned in a speech here. "How many other cities around the world could fall prey to such an attack? How many cities here, in the United States?" Mueller asked Monday in a presentation to the Council on Foreign Relations in Washington. Mueller, who took over the Federal Bureau of Investigation just days before September 11 2001, said the Mumbai attacks showed that terrorists "with large agendas and little money can use rudimentary weapons to maximize their impact." "It again raises the question of whether a similar attack could happen in Seattle or San Diego, Miami or Manhattan," he said.