A four-year-old American girl is safely in Israel after being released Sunday from captivity in Gaza, US President Joe Biden said as he urged the pause in Israel-Hamas fighting be extended to allow for more hostage releases.

"She's free and she's in Israel now," Biden said in a hastily arranged appearance before the media after the Israeli army announced that 17 hostages were being freed by Hamas.

"She's been through a terrible trauma," Biden said of Abigail, whose parents were murdered by Hamas militants when members of the Islamist group attacked Israel on October 7. On Friday in captivity, she marked her fourth birthday, the president said.

"Today, she's free, and Jill (Biden) and I, together with so many Americans, are praying for the fact that she is going to be alright," he said.

"She is now safely in Israel, and we continue to press and expect additional Americans will be released as well. And we will not stop working until every hostage is returned to their loved ones."

The White House has said that 10 Americans — seven men, two women, and Abigail — were missing and presumed held hostage by Hamas.

Biden said a total of 58 hostages have now been released by Hamas during the current temporary halt in fighting, through what he called "intensive US diplomacy" by himself and administration officials working with Israel, Qatar, Egypt, and others.

The US president said he hoped to see the pause extended.

"That's my goal, that's our goal, to keep this pause going beyond tomorrow so that we can continue to see more hostages come out and surge more humanitarian relief into those in need in Gaza."

The three-day-old truce "is delivering live-saving results," Biden added.

"Critically needed aid is going in, and hostages are coming out."