Israel-Gaza updates: 22, including 18 children, reported dead in Rafah strikes

President Joe Biden's plan to use the military to build a giant pier off the coast of Gaza to deliver food, water and medicine will cost at least $180 million and could top $200 million, ABC News has learned.

The price tag was described by two people familiar with the initial estimate, which has not been released by U.S. Central Command.

The price tag is expected to fluctuate as U.S. officials scramble to finalize key details on the project, including which humanitarian organizations and foreign governments are willing to help carry the shipments to shore and distribute them.

The floating dock is expected to be nearly the size of a football field -- about 97 feet wide and 270 feet long -- stationed about 3 miles offshore. Container ships would screen their cargo in Cyprus before taking it to the floating dock and unloading it. From there, the aid would be moved aboard small Army ferries that would transport it to an 1,800-foot "trident" pier that connects to shore.

Officials also continue to discuss how to protect the service members who will be 3 miles offshore, where Hamas is believed to still operate.

The project -- which triggered the deployment of six Army and Navy ships and will involve some 1,000 U.S. military troops -- is on track to become operational in early May, enabling the delivery of some 2 million meals per day.

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-ABC News’ Anne Flaherty and Luis Martinez

The Israel Defense Forces said 468 aid trucks entered Gaza on Tuesday -- the highest number to enter Gaza in one day since the war began.

More than 1,200 aid trucks have entered Gaza over the last three days, according to the IDF and Israeli aid agency COGAT.

Secretary of State Antony Blinken spoke emotionally Tuesday about the Americans directly impacted by the Israel-Hamas war, touching on both the hostages still held captive and the aid workers killed in Gaza.

At a news conference with his United Kingdom counterpart, David Cameron, Blinken was asked about Rachel Goldberg, whose 23-year-old son, American-Israeli Hersh Goldberg-Polin, was captured by Hamas. Goldberg is asserting that negotiators have failed.

"I know Rachel well. If I were sitting in her shoes, I'd undoubtably be feeling and saying the same thing," Blinken said. "Because until the day that Hersch is home, we will not have succeeded in doing what we're determined to do -- which is to bring him and bring all the hostages back."

Blinken also said he spoke with the family of Jacob Flickinger, a 33-year-old dual U.S.-Canadian citizen who was one of the seven World Central Kitchen aid workers killed by an Israeli strike in Gaza last week.

"I spoke over the weekend to Jacob's father and to his partner. I heard directly from them," he said. "Separately, Jacob leaves an 18-month-old son. Leaving everything else aside, just on a purely human level, my heart goes out to that family and to that little boy who now has no father."

-ABC News’ Shannon Crawford

Asked about Israeli Prime Minister Benjamin Netanyahu’s claim that Israel had set a date for its offensive in Rafah in southern Gaza, Secretary of State Antony Blinken told reporters Tuesday that the U.S. was in the dark. But Blinken added that he doesn't think the operation is imminent.

"No, we do not have a date for any Rafah operation -- at least one that's been communicated to us by the Israelis," Blinken said at a news conference with his United Kingdom counterpart, David Cameron. "On the contrary, what we have is an ongoing conversation with Israel about any Rafah operation. The president has been very clear about our concerns -- our deep concerns about Israel's ability to move civilians out of harm’s way."

Blinken said he expected talks between Israeli and American officials on the matter would press on into next week and that he didn’t want to "prejudge" an outcome.

"I don't anticipate any actions being taken before those talks," he said. "I don't see anything imminent."

As other Biden administration officials have done, Blinken stressed that the administration’s evaluation of Israel’s efforts to meet dire humanitarian needs in Gaza would be ongoing, and that officials would be "looking at a number of critical things that need to happen in the coming days."

Blinken said that list of items includes: opening a new portal for aid in northern Gaza; using Israel’s Port of Ashdod to bring in supplies on a regular basis; maximizing the flow of assistance from Jordan; repairing water lines throughout Gaza; and "putting in place a much more effective deconfliction mechanism with the humanitarian groups that are providing assistance."

-ABC News’ Shannon Crawford