Washington: US Attorney General Eric Holder said on Sunday that there was no "credible information" as yet that al Qaeda was behind the attacks in France that killed 17 people.
Holder spoke as dozens of heads of states joined hundreds of thousands of people in a massive display of unity and defiance against terrorism on the streets of Paris.
"At this point, we don't have any credible information that would allow us to make a determination as to which organisation was responsible" for the attacks this week, Holder said in an interview from Paris with ABC's "This Week."
"We'll certainly have to see exactly who was responsible (to) determine what kind of retaliation would be appropriate," he said. "But we stand in solidarity with the French."
The White House, meanwhile, announced it was organising a February 18 summit on how to fight "violent extremism around the world."
The gathering will "bring together all of our allies to discuss ways in which we can counteract this violent extremism that exists around the world," Holder said.
"Only if we work together, through sharing of information, by pooling our resources, will we ultimately be able to defeat those who are in a struggle with us about our fundamental values."
France's Ambassador to the United States Gerard Araud told ABC's "This Week", that all that was known for certain was that Coulibaly and the Kouachi brothers were friends, and that Coulibaly had said their actions were coordinated.
"But at this stage of the investigation, it's too early to go beyond that."
"It's very likely, unfortunately, that we are going to face other attempts of terrorist acts," he said.
General Martin Dempsey, the chairman of the US Joint Chiefs of Staff, echoed Holder's remarks on the French attacks in a separate interview on Fox News Sunday.
"As far as whether it was directed by Al-Qaeda, I don't think that linkage has been established," he said.