The war between Israel and the Hamas terrorist group is expected to last all of 2024, a spokesman for the Israel Defense Forces said Sunday.

Rear Adm. Daniel Hagari said in a statement that the Israeli military is making adjustments to its deployment of troops in the Gaza Strip as it anticipates the war lasting for the entirety of 2024.

"We are adjusting the fighting methods to each area in Gaza, as well as the necessary forces to carry out the mission in the best way possible," Hagari said. "Each area has different characteristics and different operational needs."

Hagari added that as 2024 begins, "The goal of the war requires lengthy fighting, and we are prepared accordingly."

The Israeli military, according to Hagari, will be carrying out "smart" management of its forces in Gaza, allowing reservists to return home to help boost the economy, and allowing standing army troops to train to become commanders.

"It will result in considerable relief for the economy, and will allow them to gain strength for operations next year, and the fighting will continue and we will need them,” Hagari said.

He said the adjustments are necessary for the IDF to endure the long road ahead.

"The IDF needs to plan ahead, out of the understanding that we will be needed for additional missions and continued fighting during the entire coming year,” Hagari said.

ABC News' Jordana Miller

In 10 posts on X, formerly known as Twitter, in 10 different languages, Israeli President Isaac Herzog issued a New Year's call to world leaders and people around the globe to advance the immediate return of the hostages being held by Hamas in Gaza.

"As we enter 2024, I call on the entire family of nations, on all world leaders, to demand and work for the immediate, unconditional release of our 133 hostages," he wrote Sunday.

"Their immediate release is at the core of our battle with Hamas terrorists in Gaza," he added.

According to the Israeli prime minister's office, there are 129 hostages being held by Hamas -- including at least 23 people believed to be dead whose bodies are still being held in Gaza.

-ABC News' Edward Szekeres

A quarter of the population is starving because too few trucks enter with food, medicine, fuel and other supplies, according to U.N. monitors.

U.N. monitors said operations at the Israeli-run Kerem Shalom crossing halted for four days this week because of security incidents, such as a drone strike and the seizing of aid by desperate Gaza residents. They said the crossing reopened Friday, and that a total of 81 aid trucks entered Gaza through Kerem Shalom and the Rafah crossing on the Egyptian border -- a fraction of the typical pre-war volume of 500 trucks a day.

The United Nations Agency for Palestine Refugees said Friday that Israeli soldiers fired on a U.N. aid convoy returning from a delivery in northern Gaza, an incident U.N. humanitarian chief Martin Griffiths condemned as "unlawful."

Palestinians reported fierce Israeli tank fire and aerial bombing in Khan Younis in southern Gaza overnight, and strikes appear to be continuing this morning.

Israel said its forces in Gaza eliminated "dozens of terror operatives" in the past day. Planes also carried out a series of air strikes on the Nuseirat camp in central Gaza, according to medics and Palestinian journalists.

Residents in the urban refugee camp of Bureij, a recent hot spot of combat along with Nuseirat, also reported Israeli airstrikes overnight and into Saturday. Israeli forces have been pounding Khan Younis in preparation for an anticipated further advance into the main southern city, swaths of which they captured in early December.

Israel said Saturday its troops have advanced further in southern Gaza, while raiding Hamas sites in Khan Younis, including the headquarters of the terror group’s intelligence division in the city.

According to Israel, the intelligence HQ was responsible for all of Hamas’s intelligence activity in the Khan Younis area.

The Israel Defense Forces claimed on Sunday that it has "completed the dismantling of Hamas' military framework" in the northern Gaza Strip, hitting hundreds of targets and taking out key leaders of the terrorist group.

In an assessment of the first three months of the war between Israel and Hamas, Rear Adm. Daniel Hagari, an IDF spokesperson, said Israeli forces have met their goals through airstrikes, ground operations and intelligence gathering in the primary objective of eliminating Hamas.

He said the IDF's efforts in northern Gaza have included a relentless barrage of missile strikes, most of them targeting Jabaliya, the onetime stronghold of Hamas. In Jabaliya alone, Hagari said IDF airstrikes had hit 670 targets before ground forces entered the area and another 300 targets after ground troops moved in and helped direct precision airstrikes.

"In these strikes in the Jabaliya area, we eliminated the battalion commander, the deputy brigade commanders, and 11 company commanders leading the terrorists in the field," Hagari said during a news conference.

Among the Hamas commanders eliminated was Ahmad Randor, Hagari said, showing what he said was a photograph of Randor sitting with his command echelon in a bunker 40 meters, or about 131 feet, underground.

"We have completed the dismantling of Hamas' military framework in the northern Gaza Strip and will continue to deepen the achievement, strengthening the barrier and the defense components along the security fence," Hagari said.

Since the war started, IDF forces have located and destroyed 40,000 weapons across the Gaza Strip, some of which were found in schools, hospitals, mosques, and even under the beds of children, Hagari said. In Jabaliya, IDF troops also infiltrated about 5 miles of tunnels and more than 40 tunnel shafts leading to Hamas' northern headquarters and retrieved the bodies of five hostages, according to Hagari.

"Hamas no longer operates in an organized manner in this area. We have deprived it of its main terror capabilities in the region," Hagari said.

He noted that while there are still terrorists in the Jabaliya area, "they now operate without a framework and without commanders."

-ABC News' Jordana Miller