Hamas's armed wing said on Saturday the fate of Israeli-American hostage Edan Alexander was unknown after the group found the guard who was holding the hostage killed.
On Tuesday, Hamas said it had lost contact with a group of its members holding Alexander in Gaza after the Israeli army attacked the place where the militants were holding him.
Alexander is a New Jersey native and a 21-year-old soldier in the Israeli army.
"We are trying to protect all the hostages and preserve their lives ... but their lives are in danger because of the criminal bombings by the enemy's army," the armed-wing Al-Qassam Brigades's spokesperson, Abu Ubaida, said, reiterating an accusation that Israel's army is to blame for the killing of hostages in the enclave, Reuters reported.
Israel has accused Hamas of killing hostages in its custody.
"The fate of the prisoner (hostage) and the rest of the captors remains unknown," Abu Ubaida added.
There was no immediate comment by the Israeli army on Hamas's statement. Israeli Prime Minister Benjamin Netanyahu is scheduled to give a statement later on Saturday.
The release of Alexander was at the center of earlier talks held between Hamas leaders and US hostage negotiator Adam Boehler last month.
President Donald Trump's special envoy Steve Witkoff told reporters at the White House in March that gaining the release of Alexander, believed to be the last living American hostage held by Hamas in Gaza, was a "top priority".
Hamas so far released 38 hostages under a brief ceasefire that began on January 19.
Israel resumed its offensive in Gaza in March after ceasefire talks stalled, with both sides blaming one another for the failure to reach an agreement.
Israel says its offensive in Gaza aims to release the remaining 59 hostages, while Hamas insists it will free hostages only as part of a deal to end the war and has rejected demands to lay down its arms.
