US President Barack Obama has directed his counter-terrorism officials to redouble their efforts for investigating specific and credible terror threat. It has come ahead of the 10th anniversary of 9/11 attacks. The President was briefed on this specific threat information.The United States government has already significantly enhanced its security posture in advance of the 9/11 anniversary to protect the country against possible terrorist threats. In a statement, the Department of Homeland Security said that there is a specific, credible but unconfirmed threat information.