Hamas released new undated video footage on Saturday of two men— including an American citizen — held hostage in Gaza. The video shows the two men alive and was released on the Palestinian militant group's social media channel, which is regularly used by the group to publish propaganda videos.

The hostages seen on the video were identified as Omri Miran and Keith Siegel by the campaign group the Hostages and Missing Families Forum. Both men were abducted by militants during the Hamas attack on Israel on Oct. 7.

In the statement, the campaign group said the video shows the hostages "for the first time after 204 days in captivity." CBS News can't verify the date of filming or the contents of the video, but the footage was posted on the channel where it has posted other videos showing hostages.

A U.S. official told CBS News that the FBI is reviewing the proof of life propaganda video released by Hamas, which features U.S. citizen hostage Siegel along with an Israeli hostage. The White House did not have advance notice of the Siegel video prior to its public release. U.S. officials are in contact with the Siegel family.

There are five U.S. nationals still unaccounted for and presumed to be living hostages in Gaza, a U.S. official confirmed to CBS News on Wednesday. The remains of three other U.S. citizens are believed to be in their possession. Hamas released video footage of Israeli-American Hersh Goldberg-Polin on that day — while Jews were celebrating Passover — and he delivered a long statement clearly crafted by Hamas.

It was the first time Hamas publicly released a video of a U.S. citizen held hostage, the U.S. official said, until Saturday when the video of Siegel appeared. He is the second U.S. citizen to appear in a Hamas propaganda video. A representative for the family of Siegel told CBS News that this is the first such video that the family has seen of the 64-year-old American since he was abducted.

Siegel's wife, a woman named Aviva Siegel, who is not a U.S. citizen, was released by Hamas in November during a temporary cease-fire in which the militant group released about 100 hostages taken during the militant group's Oct. 7 attack on Israel. Some 210 Palestinians have been released from Israeli prisons in return. 

Hamas and associated terror groups are believed to be holding 133 hostages in Gaza.

"The proof of life from Keith Siegel and Omri Miran is the clearest evidence that the Israeli government must do everything to approve a deal for the return of all the hostages before Independence Day. The living should return for rehabilitation, and the murdered should receive a dignified burial," the campaign group's statement said. 

— Tucker Reals, Margaret Brennan, Pat Milton,  and Haley Ott contributed reporting.

In:
• Hostage Situation
• Hamas
• Israel