NEW YORK — US President Barack Obama said Monday that the attack on the US consulate in Libya's Benghazi was clearly more than a "mob action," amid lingering dispute about the nature of the assault.

Obama also said in an appearance on the ABC talk show "The View" that the best way to deal with a film deemed offensive to Muslims like the one which sparked anti-US fury in the Middle East was to ignore it.

"There's no doubt that the kind of weapons that were used, the ongoing assault, that it wasn't just a mob action," Obama said of the Benghazi attack two weeks ago which killed US ambassador to Libya Christopher Stevens and three other Americans.

The White House said for the first time last week that the attack was terrorism, under heavy political pressure from Republicans.

But there is still dispute about whether the assault was a planned Al-Qaeda operation involving foreign militants or was a case of local extremists exploiting an anti-US protest to target the US mission.

FBI agents are in Libya probing the evidence and Secretary of State Hillary Clinton has ordered a State Department review of issues including whether lax security around Stevens contributed to the attack.

Obama, who is in New York ahead of his annual address to the United Nations on Tuesday, said despite anger over the film "Innocence of Muslims" there was no excuse for violence.

"The best way to marginalize that kind of speech is to ignore it," he said.

And in a theme he is likely to strike in his remarks to the UN General Assembly, Obama reiterated that the "overwhelming majority" of Muslims bore no threat to the United States.

"They want the same things that families here want. They want opportunity, kids want an education, they want jobs, they want peace. But there are extremist strains that are there," Obama said.