National security adviser Jake Sullivan said Sunday that nine Americans and one green card holder were still unaccounted for following the Hamas attack on Israel on Oct. 7.

In an interview on CNN’s “State of the Union,” Sullivan said U.S. officials did not know whether those 10 people were still alive, but that “active, intensive negotiations” were underway to secure the release of all hostages.

“We currently have nine Americans who are missing, one green-card holder who is missing. We don’t know the status — whether they are alive or whether they have passed away — but we are looking to get the safe recovery of all of those individuals,” Sullivan told CNN’s Dana Bash.