Americans have stocked up on emergency supplies. Terrorist suspects probably lied when they warned that attacks on the United States were imminent, Bush administration officials have said. But they added that the dubious tip-offs were not the sole basis for raising the alert across the US last week to orange, the highest level since the anniversary of the 11 September attacks. Separately, Homeland Security Secretary Tom Ridge said there was no need to panic, though Americans were wise to take precautions. Security has increased visibly in US cities. There has been mass buying of supplies by people preparing to create shelters for a radiological or chemical attack. Security was increased at sites across the US after intelligence officials decided there was a clear danger. Full Story