WASHINGTON - US President Barack Obama on Tuesday warned against the threat of "lone wolf" terror attack to the United States, as the tenth anniversary of the 9/11 attacks approaches.

"The most likely scenario that we have to guard against right now ends up being more of a lone wolf operation than a large, well- coordinated terrorist attack," Obama said in an interview with CNN.

He said such attack would look like what took place in Norway last month, when one person killed dozens of people without elaborate organizational support.

"When you've got one person who is deranged or driven by a hateful ideology, they can do a lot of damage, and it's a lot harder to trace those lone wolf operators," said the president.

However, Obama said the government is still monitoring all potential terror scenarios and is keeping its vigilance, especially with the 9/11 anniversary approaching.

He said the United States is making progress in pressing al-Qaida, and "they are a much weaker organization with much less capability than they had just two or three years ago." ?

On September 11, 2001, al-Qaida terrorists hijacked four commercial passenger planes and crashed two into the Twin Towers of the World Trade Center in New York City, leaving some 3,000 people dead.