Hamas released a video on Sunday showing three Israeli hostages who are still being held in captivity in Gaza.

The three hostages that appear in the video are 26-year-old Noa Argamani, 35-year-old Itai Svirsky and 53-year-old Yossi Sharabi.

The video released by Hamas called on Prime Minister Benjamin Netanyahu to end the war on Gaza.

-ABC News' Ellie Kaufman

President Joe Biden on Sunday marked 100 days since Hamas launched its deadly attacks on Israel on Oct. 7, vowing to get more of the American hostages freed.

"For 100 days, they have existed in fear for their lives, not knowing what tomorrow will bring," Biden said of the hostages held by Hamas in Gaza.

"For 100 days, their families have lived in agony, praying for the safe return of their loved ones," Biden added, saying the families have been "at the forefront of my mind."

"No one should have to endure even one day of what they have gone through, much less 100," he said.

"We will never stop working to bring Americans home," Biden pledged.

-ABC News' Fritz Farrow

As the Israel-Hamas war reached its 100th day Sunday, the Israel Defense Forces says it's goals "will take a long time" to achieve.

"To achieve real results, we must continue to operate in enemy territory, not to allow extortion attempts for a cease-fire," IDF Lt. Gen. Herzi Halevi said in a televised address Saturday.

"We must continue applying pressure and that is exactly what we are doing," he said. "[Our] goals are complex to achieve and will take a long time. To dismantle Hamas, patience is both necessary and essential."

The IDF also said it's now moving to intensify its operations in southern Gaza, where it believes Hamas' leadership is hiding.

-ABC News' Patrick Reevell

The U.S. ambassador to Israel, Jack Lew, addressed a rally in Tel Aviv on Sunday demanding the immediate return of the hostages still being held by Hamas.

"One day is too many -- 100 days is unfathomable," Lew told the crowd. "My heart aches for all who have been affected by Oct. 7 and I stand in solidarity, as does the United States, with the families of the hostages. I add my voice to theirs to say: Bring them home now."

Tens of thousands of Israelis have rallied over the last 24 hours to demand the return of the hostages on the 100th day of their captivity.

-ABC News’ Patrick Reevell

Israel is defending itself in the United Nations' top court starting Thursday against allegations that its ongoing military campaign in the neighboring Gaza Strip amounts to genocide of the Palestinian people -- a claim that Israel vehemently denies.

South Africa, which brought forward the allegations, is initially asking the Netherlands-based International Court of Justice to order an immediate suspension of the Israeli military offensive against Gaza's militant rulers, Hamas, as part of a landmark case that is likely to take years to resolve.

"Genocides are never declared in advance, but this court has the benefit of the past 13 weeks of evidence that shows incontrovertibly a pattern of conduct and related intention that justifies as a plausible claim of genocidal acts," South African attorney Adila Hassim told the panel of judges inside a packed courtroom in The Hague during Thursday's opening statements. "Nothing will stop the suffering except an order from this court."

South Africa insists Israel is committing genocide by design and that the country's latest war in Gaza is part of its decadeslong oppression of Palestinians. South Africa's ruling political party, the African National Congress, has a long history of solidarity with the Palestinian cause and sees parallels with its own struggle against the apartheid regime of white minority rule that ended in 1994.

"The violence and the destruction in Palestine and Israel did not begin on Oct. 7, 2023," South African Justice Minister Ronald Lamola said. "The Palestinians have experienced systematic oppression and violence for the last 76 years."

Israeli President Isaac Herzog has called South Africa's allegations “atrocious and preposterous,” while Secretary of State Antony Blinken has dismissed the case as "meritless."

Israeli Prime Minister Benjamin Netanyahu in response Thursday called South Africa's allegations "upside-down."

"Israel is fighting against murderous terrorists who have committed terrible crimes against humanity: they slaughtered, they raped, they burned, they dismembered, they killed children, women, the elderly, young men, young women. A terrorist organization that committed the most terrible crime against the Jewish people since the Holocaust, and now there are those who come to defend it in the name of the Holocaust," Netanyahu said. "We will continue to fight the terrorists, we will continue to repel the lies, we will continue to maintain our right to defend ourselves and secure our future."

National Security Council spokesman John Kirby called South Africa’s case "unfounded" and reiterated that "Israel has a right and responsibility to defend itself."

"We're going to continue to supply them with the tools and capabilities they need to do that," Kirby said Thursday.

Lawyers for Israel will address the court on Friday.

-ABC News' Joe Simonetti, Edward Szekeres and Morgan Winsor