Hamas said on Friday that it had agreed to free Edan Alexander, an American Israeli soldier who has been held in Gaza for 17 months, and return the remains of four other hostages, without specifying when they would be released or what it was demanding in exchange.

Israel did not immediately comment on Hamas’s statement. Benjamin Netanyahu, the Israeli prime minister, convened a security meeting to discuss the matter, said an Israeli official, who spoke on condition of anonymity because they were not authorized to speak publicly.

In its statement, Hamas said it had received a proposal from unnamed mediators to which it submitted a formal response that included turning over Mr. Alexander and the four bodies.

But it was still unclear whether Israel and Hamas were actually close to a deal and whether Israel would assent to any stipulations.

Israel and Hamas are supposed to be negotiating the second phase of the Gaza cease-fire and hostage release deal that began in January. But those talks have seen little progress given entrenched disputes between the two sides over who will control the Palestinian enclave.

Last week, the Trump administration held meetings with Hamas, sidestepping the deadlocked Israeli-Hamas negotiations, in an attempt to free the remaining American hostages held in Gaza. Adam Boehler, President Trump’s nominee for special envoy for hostage affairs, met with senior Hamas officials in Doha.

Hamas and other militant groups seized about 250 hostages during the Oct. 7, 2023, attack on southern Israel that ignited the war in Gaza. More than 100 have returned alive to Israel after deals with Hamas in exchange for Palestinian prisoners. Israeli soldiers retrieved the bodies of dozens of others during their ground invasion of Gaza.

Up to 24 living hostages and the bodies of at least 35 others are still in Gaza, according to the Israeli government. They include five Americans: Mr. Alexander, the last American-Israeli hostage still believed to be alive, and four others who are presumed dead.