Terrorism, September 11 Anniversary | featured news

Swedish police arrested four people on suspicion of preparing a terror attack and evacuated an arts center in Sweden's second largest city on the eve of the 9/11 anniversary, officials said Sunday.

A mother in Malaysia greeted her dead son. People in Manila left roses for the victim who helped give them homes. And mourners in Tokyo stood before a piece of steel from ground zero, remembering the 23 bank employees who never made it out alive.

A hacker broke into the Twitter account of NBC News and sent out a handful of false tweets about a suspected hijacking and a plane attack at ground zero just days before the tenth anniversary of 9/11.

On Thursday, U.S. government officials warned of a credible but unconfirmed threat of terrorist activity tied to the 10th anniversary of the Sept. 11, 2001, terrorist attacks. That may have some travelers wondering, should I take extra precautions? The consensus: No need to stay home, but on this day especially, be alert.

U.S. officials said Thursday evening they have "specific, credible but unconfirmed" information about a potential threat against the United States coinciding with the 10th anniversary of the September 11 terrorist attacks.