Another 17 people were freed by Hamas on Sunday in the third day of hostage releases, including the first with U.S. citizenship: a four-year-old girl whose parents were killed in the Oct. 7 attacks.

Abigail Idan, one of three hostages with American citizenship, was initially in the hands of the International Committee of the Red Cross. Hamas militants killed her parents at their home on the Kfar Aza kibbutz near the Gaza border.

“One of our fellow Americans, a little girl named Abigail turned 4 years old — she spent her birthday, that birthday and at least 50 days before that held hostage by Hamas,” President Joe Biden said Sunday in Nantucket, where he spent the holidays. “She’s free and she’s in Israel now.”

“What she endured is unthinkable,” he added.

The total number of people released to the care of the Red Cross included 13 Israelis, three foreign nationals and an individual carrying a Russian passport, in exchange for 39 Palestinian prisoners, said Qatar’s Foreign Ministry spokesperson Majed Al-Ansari. Unlike the previous two nights, the hostages were released in the northern part of the Gaza Strip.

The foreign nationals were from Thailand, according to Qatar. Earlier, U.S. National Security Adviser Jake Sullivan said he had “reason to believe” at least one American citizen would be among those released.

Talks are continuing to extend the four-day cease-fire as more humanitarian aid trucks headed into Gaza on Sunday, including northern areas.

“We are making every effort to return our hostages, and we will return them all,” Israeli Prime Minister Benjamin Netanyahu said in a statement.

The prime minister’s office said earlier it had received a list of names of abductees whom Hamas was due to hand over on Sunday. The Palestinian militant group that governs Gaza freed a total of 26 Israelis, some with dual nationalities, as well as 14 Thai nationals and one Filipino citizen on Friday and Saturday.

The releases made in several stages are key to a deal brokered by Qatar and Egypt that’s brought a pause of fighting in the more than six-week war, and allowed the flow of further humanitarian aid into besieged Gaza.

Separately on Sunday, Hamas said it would release a dual Israeli-Russian hostage “in response to the efforts of Russian President Vladimir Putin and in appreciation of the Russian position in support of the Palestinian cause.” That individual appears to have been counted among the 14 Israeli detainees.

Lolwah Al-Khater, Qatar’s minister of state for international cooperation, told Al-Jazeera TV that work continues at the political level to extend the current truce, which has been scheduled to run for four days.

An hours-long delay to Saturday’s releases, blamed by Hamas on Israel, underscored the shakiness of the short-term truce. Hamas is designated by the U.S. and European Union as a terrorist group. The militants infiltrated Israel on Oct. 7, killing 1,200 people and abducting about 240 others.

Israel has unleashed its military might on the small, crowded Gaza Strip since the attack. At least 15,000 people have been killed, according to the Hamas-run health ministry.

The Palestinian prisoners released were children and young men, ages 15-19, largely accused of public disorder, property damage and in some cases causing or threatening physical harm to Israeli officers by throwing stones and Molotov cocktails. Many were scooped up from protests and confrontations with troops. In turn, many Palestinians view prisoners held by Israel, including those implicated in attacks, as heroes resisting occupation.

A fourth exchange is expected on Monday — the last day of the cease-fire during which a total of 50 hostages and 150 Palestinian prisoners are to be freed. Most are women and minors.

This handout photo provided by the Israel Prime Minister Office shows Naveh Shoham, 8 years-old, upon his arrival in Israel after being freed. (Israel Prime Minister Office/Handout via AP)
Abigail Idan, 4, was one of the third group of hostages released by Hamas on Sunday as part of truce deal. (Hostages and Missing Families Forum headquarters via AP)