White House officials confirmed Tuesday that at least one more U.S. national is being held captive in the region where the Islamic State group recently executed another American hostage.

White House Press Secretary Josh Earnest made the announcement at a press conference, but would not discuss details as the administration does not wish to publicly identify hostages, the Washington Times reported, adding that he also did not confirm if the hostage was being held by ISIS.

“There is at least one other hostage that is being held in the region,” he told reporters.

News agencies speculated that the hostage might be journalist Austin Tice, who went missing in the Syrian capital of Damascus in 2012, Deutsche Welle reported. Tice’s family has reportedly said he’s being held in the area, though not by ISIS or the Syrian government, Mashable reported.

Tice’s parents have been advocating for greater family involvement in hostage recovery programs, asking for families to have a role in an ongoing review of U.S. hostage policy.

The White House announcement came hours after the administration confirmed the death of 26-year-old aid worker Kayla Mueller, who had been captured while leaving a Doctors Without Borders camp in Aleppo, Syria. ISIS had previously claimed that Mueller had died during a Jordanian air strike, but U.S. officials confirmed that she died while being held captive by ISIS.

In 2012, a video was circulated online showing Tice being held by armed men. Two years after his disappearance, Tice’s parents published a letter in August, saying they have had no contact with either their son or his captors since his disappearance, and did not know his fate. Since then, his family has launched the Free Austin Tice campaign, in coordination with Reporters Without Borders, to urge the U.S. government to take action on Tice’s behalf.

"I hope it will contribute to bringing him back home, and I think [it] is a very important moment because he is the only American journalist still missing in Syria and we can bring him back home," Delphine Halgand, the U.S. director for Reporters Without Borders, told Mashable.