U.S. officials say, they have discovered information about what they are calling a ‘credible threat’ of a specific attack planned to coincide with the 10th anniversary of the September 11, 2001 terrorist attacks. Sources told U.S. news media Thursday the information suggests the threat may focus on Washington, DC or New York City. Officials say, the threat is unconfirmed and that they are continuing to investigate. They say they are considering whether to brief local police about what to look for and whether to make the information public. The government is also considering whether to raise the country's terrorist alert level. Earlier, Homeland Security Secretary Janet Napolitano said intelligence officials have lately picked up more ‘chatter’ on terrorist websites. She said the U.S. is taking all of the talk seriously.