Less than 1,000 U.S. service members will remain in northern Syria to ensure the lasting defeat of the Daesh/ISIS terror group, U.S. Joint Chiefs Chairman Mark Milley said in remarks aired Sunday.

Milley told ABC News that the number would be “for sure” less than that level, but he did not specify an exact number other than saying it would likely be around 500 to 600.

“It’s in that area,” he said on the This Week Sunday morning program. “We’re not going to go into specific number because we’re still going through the analysis right now.”

Read more: Less than 600 US troops to remain in Syria: top gen