Israel-Gaza live updates: Israel 'deepening the war' in Gaza: Netanyahu

Secretary of State Antony Blinken said the U.S. is heading into next year focused on ensuring that Hamas’ Oct. 7 attack on Israel cannot happen again, as well as bringing the conflict in Gaza to an end as quickly as possible.

“We're more determined than ever to ensure that out of this horrific tragedy comes a moment of possibility for Israelis, for Palestinians, for the region, to live in lasting peace and lasting security,” Blinken said at his end-of-year news conference Wednesday.

Blinken spoke about the need to downshift the scale of warfare, but he didn’t set a firm timeline.

“It’s clear that the conflict will move and needs to move to a lower intensity phase. And we expect to see, and want to see, a shift to more targeted operations with a smaller number of forces that's really focused in on dealing with the leadership of Hamas, the tunnel network and a few other critical things,” Blinken said. “As that happens, I think you'll see as well, the harm done to civilians also decrease significantly.”

Blinken also addressed intense negotiations over an Arab-sponsored United Nations Security Council resolution to ramp up humanitarian aid deliveries to Gaza and impose a halt in the fighting. That resolution is expected to come to a vote soon and it’s possible that the U.S. could veto it.

The secretary said the U.S. wanted to make sure the measure would actually advance the effort to move aid into Gaza and “doesn't do anything that could actually hurt the delivery of humanitarian assistance -- make it more complicated.”

He added that the U.S. was engaged “in good faith with other countries.”

“We've been working this intensely. I've been on the phones about this for the last the last couple of days,” Blinken said. “So, I hope we can get to a good place.”

-ABC News’ Shannon Crawford

The death toll in Gaza since the start of the Israel-Hamas war has now surpassed 20,000, according to the Hamas-run Gaza Ministry of Health.

President Joe Biden called the death toll "tragic."

As the death toll in Gaza nears 20,000, National Security Council spokesman John Kirby said Wednesday that "the right number of civilian casualties is zero."

“There's no number of an innocent civilian killed or wounded that's acceptable, nor should it be acceptable by anybody, which is why we're going to continue to work with the Israelis about being more precise, more targeted, more delivered in their military operations," Kirby said.

He said Israel has “taken on our concerns, and they have been receptive, and they have adapted their military operations to try to bring the number of civilian casualties down.”

“We want to see the number zero, but they have made some efforts,” Kirby added.

-ABC News’ Karen Travers and Cheyenne Haslett

The Palestinian Islamic Jihad released a video on Tuesday of two Israeli hostages pleading for their release.

The men -- who identified themselves as Gadi Moses and Elad Katzir -- spoke as they appeared in front of a plain background in the nearly 2 1/2-minute video.

"I want to convey to my friends and supporters that we must increase the pressure so that the government understands what we want," Moses said in the video provided by the hostage-takers. "We want every effort to be made so that we will soon arrive back home to our friends, our family, to our home."

Addressing Israeli leaders, including Prime Minister Benjamin Netanyahu and Israel Defense Forces Commander Hertzi Halevi, Moses said he feared being killed by an Israeli bomb.

"This situation where we could die at any moment is an unbearable situation; there is a reasonable chance that we will also be killed tonight," he said.

Katzir, 47, also said the bombings "endanger our lives" and urged Israeli leaders to make a prisoner exchange deal.

"We don't want to die in Gaza," he said. "We want them to do whatever it takes to bring us home."

It is unclear when the video was recorded and if the men were told what to say.

The hostages' families gave ABC News permission to use stills from the video.