"And unless that changes strategically, we can expect more attacks like this," said Adam Schiff, the ranking Democrat on the House Intelligence Committee.
His comments on ABC's "This Week" come amid growing questions about a US-led strategy that has relied on air strikes to try to roll back IS in Syria and Iraq while picking off its leaders one by one.
The international response to the attacks was the focus of a summit in Turkey, including US President Barack Obama who vowed to stand by France and "redouble" efforts to wipe out jihadist networks.
"This was an ISIS attack likely directed and equipped out of Syria," Schiff said, adding that France has been the primary focus of IS attacks for the past year.
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"They have wanted to attack in public places like we saw, so tragically this week," he said.
He said even the best intelligence was not enough to stop attacks by an enemy that is adapting to the West's defenses, as IS has.
The US deputy national security adviser, Ben Rhodes, said on the same program that the United States will intensify air strikes, the training and equipping of forces on the ground and the targeting of IS leaders.
The US believes that by intensifying those efforts "we'll be able to roll back ISIL and ultimately achieve that objective of defeating the organization," Rhodes said.
"I think that the chief failure here is we cannot allow ISIS to have this unmolested sanctuary in Syria and Iraq from which to plan and direct attacks against us, because some of those attacks will get through," he said.