Israel on Tuesday said it plans to expand ground fighting in central Gaza Strip's densely populated refugee camps and that its war on Hamas could last several more months, raising concerns from the United Nations.
"There are no short cuts in dismantling a terrorist organization," army chief Herzi Halevi said Tuesday, referring to Hamas militants.
The Israeli military said it attacked more than 100 targets, including tunnel shafts and sites used by Hamas militants to organize attacks against Israeli forces.
Israeli military spokesman Rear Admiral Daniel Hagari said, "We have expanded the fighting to an area known as the central camps."
The expansion of fighting in central Gaza prompted the United Nations on Tuesday to voice alarm over Israeli attacks that killed more than 100 Palestinians in the past two days.
"We are gravely concerned about the continued bombardment of Middle Gaza by Israeli forces, which has claimed more than 100 Palestinian lives since Christmas Eve," U.N. Human Rights Office spokesperson Seif Magango said on Tuesday.
"Israeli forces must take all measures available to protect civilians. Warnings and evacuation orders do not absolve them of the full range of their international humanitarian law obligations," Magango said.
Residents reported airstrikes and shelling in the areas of the Nuseirat, Maghazi and Bureij refugee camps in central Gaza.
Radwan Abu Sheitta, who lives in Bureij, told The Associated Press by phone, "The bombing was very intense."
Israeli army chief Halevi told reporters in a televised statement on Tuesday from the Gaza border that the war would go on "for many months."
"There are no magic solutions, there are no shortcuts in dismantling a terrorist organization, only determined and persistent fighting," Halevi said. "We will reach Hamas' leadership too, whether it takes a week or if it takes months."
On Tuesday, U.S. President Joe Biden spoke by phone with Qatari Emir Sheik Tamim bin Hamad Al Thani, a White House statement said.
"The two leaders discussed the urgent effort to secure the release of all remaining hostages held by Hamas, including American citizens," the White House readout said, adding the two leaders also talked about increasing access to humanitarian aid.
Qatar and Egypt mediated the brief cease-fire and hostage exchange between Israel and Hamas in late November. However, current diplomatic efforts have fallen short.
The White House said Israeli Minister for Strategic Affairs Ron Dermer met on Tuesday with Secretary of State Antony Blinken and national security adviser Jake Sullivan for talks on a number of matters related to the conflict in Gaza.
Late Tuesday, a White House official said Sullivan and Dermer discussed transitioning to a different phase of the war to focus on high-value Hamas targets, and planning for the day after fighting ends, including governance and security in Gaza.
Earlier Tuesday, Israel returned the bodies of 80 Palestinians killed in Gaza after taking them from morgues and graves to check that there were no hostages among them, sources in the Hamas-ruled Gaza Health Ministry said.
Gaza authorities buried the unidentified bodies on Tuesday, the Health Ministry said.
On October 7, Hamas militants poured over the border with Gaza and attacked southern Israeli communities, killing about 1,200 people, according to Israel. The group, designated a terrorist group by the U.S. and others, also seized around 240 hostages, of whom 129 remain in Gaza.
In response, Israel vowed to crush Hamas and launched an air, land and sea offensive on Gaza. The Israeli offensive has left vast parts of Gaza in ruins and killed nearly 21,000 Palestinians, according to the Gaza Health Ministry.
The fighting has also displaced most of Gaza's 2.3 million people, with many trying to find safety in overcrowded, U.N.-run shelters in southern Gaza.
The Israeli army said Tuesday that 158 Israeli soldiers have been killed inside Gaza since fighting began in October.
VOA's Mykhailo Komadovsky contributed to this report. Some material for this report came from The Associated Press, Agence France-Presse and Reuters.