White House national security communications adviser John Kirby expressed confidence Thursday morning that the cease-fire and hostage exchange agreement with Hamas can proceed as planned on Sunday, despite a delay announced by Israeli Prime Minister Benjamin Netanyahu. Families of American hostages await news of their loved ones' release.

Speaking to ABC's George Stephanopoulos, Kirby confirmed the existence of a deal, stating, "We're confident that we're going to be able to start implementing it on Sunday. Some implementing details still need to be worked out, and we are actively collaborating with the Israelis on that." He reiterated his confidence in a successful resolution.

From left, American hostages being held in Gaza: Edan Alexander, Sagui Dekel-Chen, Keith Siegel, Omer Neutra, Judi Weinstein Haggai, Gadi Haggai and Itay Chen. (Fox News)

Confusion arose after Netanyahu asserted that Hamas was "creating a last-minute crisis" and "backing out of the explicit understandings" reached with mediators and Israel. He accused Hamas of a "last-minute blackmail attempt," according to a statement from Israeli news agency TPS-IL. Hamas has reportedly denied these accusations.

Netanyahu postponed a cabinet vote on the deal, stating it would not proceed until "the mediators announce that Hamas has approved all the details of the agreement." However, Kirby maintained that the deal is not collapsing, telling MSNBC, "It’s not breaking down," and NBC that the U.S. is working to resolve the outstanding issues.

Pictures of loved ones who have been captured by Hamas on display during a Defend Israeli Democracy U.K. press conference at Plaza Westminster Bridge Hotel in London, Oct. 12, 2023. (Lucy North/PA Images via Getty Images)

The first phase of the agreement calls for the release of 33 hostages, prioritizing children, women, the elderly, and those who are sick or wounded, over a 42-day period. Three hostages, potentially including Israeli female soldiers, are expected to be released on the first day. A senior administration official indicated that two of the three living American hostages, Keith Siegel and Sagui Dekel-Chen, are also expected to be released on the first day, with Edan Alexander, an American-Israeli who served in the IDF, to be released later.

Israeli hostage families carry the photos of their loved ones who are held hostage by Hamas in Gaza as they march to Jerusalem. (Matan Golan/SOPA Images/LightRocket via Getty Images)

Negotiations regarding the remaining hostages, both living and deceased, are set to commence on the 16th day of the first phase. At least 98 hostages remain in Gaza, with 62 believed to be alive and 36 presumed dead. A U.S. official affirmed the commitment to securing the release of all Americans, whether living or their remains.