The armed wing of Palestinian resistance group Hamas handed over a US-Israeli hostage held in Gaza since October 2023 on Monday, ahead of a regional visit by US President Donald Trump.
"The (Ezzedine) Al-Qassam Brigades have just released the Zionist soldier and American citizen Edan Alexander, following contacts with the US administration, as part of the efforts undertaken by mediators to achieve a ceasefire," Hamas said in a statement.
Egypt and Qatar, which along with the United States have mediated talks between Hamas and Israel, called it "an encouraging step toward a return to the negotiating table" in a joint statement.
Israel's military said he was back inside Israel to be "reunited with his family".
An Israeli Air Force helicopter was taking him to a hospital where he will receive treatment and reunite with family members.
Israel's Channel 12 said his condition was "low", without citing a source.
Hamas said it freed Alexander as a goodwill gesture to President Trump.
Flag-waving crowds gathered to greet the convoy carrying Alexander, and in Tenafly, New Jersey, where he grew up, large crowds celebrated his release.
Israeli Prime Minister Benjamin Netanyahu hailed Alexander's return. Netanyahu thanked Trump "for his assistance in the release", and also said he had instructed a negotiating team to head to Qatar on Tuesday to discuss the further release of hostages.
Alexander's release comes a day after Hamas revealed it was engaged in direct talks with Washington towards a Gaza ceasefire.
"We affirm that serious and responsible negotiations yield results in the release of prisoners, while the continuation of aggression prolongs their suffering and may kill them," a Hamas statement said.
"We urge President Trump's administration to continue its efforts to end this brutal war."
Alexander's release came with Trump heading for Saudi Arabia on the first leg of a regional tour.
Meanwhile, the UN- and NGO-backed Integrated Food Security Phase Classification (IPC) warned that Gaza was at "critical risk of famine", with 22% of the population facing an imminent humanitarian "catastrophe" after more than two months of a total aid blockade by Israel.
Gaza's civil defence agency earlier reported at least 10 killed in an overnight Israeli strike on a school housing displaced people.
After Hamas announced Sunday it would release Alexander, Trump hailed the "monumental news" in a post on social media, describing it as a "good faith gesture".
The health ministry in Hamas-run Gaza said Monday at least 2,749 people have been killed since Israel resumed its campaign, bringing the overall death toll since the war broke out to 52,862.

Newly-released Israeli-US hostage Edan Alexander talking to Israeli soldiers near a International Red Cross vehicle, at an undisclosed location.