Obama says no specific terror threat against US

President Barack Obama sought Wednesday to reassure jittery Americans traveling home for Thanksgiving that they face no credible and immediate terror threat and said that security services are working around the clock to keep the US safe. As millions of Americans loaded into cars, planes, trains and buses to head home for Thursday's national holiday, Obama urged calm. "I want the American people to know... that we are taking every possible step to keep our homeland safe," Obama said, trying to s