The U.S. Middle East envoy Brett McGurk, who is currently in Egypt to discuss the situation in Gaza, is expected to focus on a longer humanitarian pause, the White House said Tuesday.

White House spokesperson John Kirby said McGurk was also discussing other issues during his trip, including getting an assessment of Israel's military operations and its efforts to protect civilians, as well as continuing to explore the idea of normalizing Israel-Saudi ties.

Kirby said the U.S. would support a longer humanitarian pause in Gaza to ensure hostages could be released and aid brought in. He declined to specify a timeframe and cautioned he would not characterize the discussions as negotiations.

"The conversations are very sober and serious about trying to get another hostage deal in place," Kirby told a regular White House briefing, adding the talks included discussion on how long of a pause would be needed to get the hostages out.

Israel suffered its worst day of losses in Gaza, with 24 soldiers killed, the Israeli military said on Tuesday, as its forces encircled southern Gaza's main city, trapping Palestinian residents trying to flee.

When asked about media reports that a cease-fire deal was being discussed, Qatar said mediation efforts were ongoing. Israeli government spokesperson Eylon Levy said the war's goals were unchanged.

Asked how Tuesday's death toll of 24 Israeli soldiers in Gaza affected Israel's perception of the war, Kirby said only the Israelis could answer that question.

"It was a terrible, terrible day for the IDF yesterday. That's an enormous amount of troops lost in one day and certainly our condolences go out to all the families and their teammates as well," he said.

Kirby reiterated Washington's insistence that future post-conflict Gaza leadership could not include Hamas leaders and said Washington did not want the territory of Gaza reduced.

"Whatever governance looks like in Gaza, after this is over, it's got to be representative of the aspirations of the Palestinian people who are not represented by Hamas," he said.

Kirby also rejected plans by Israel to establish a "buffer zone" within the Gaza Strip and said such a proposal is at odds with the Biden administration's stated policy.

"We do not want to see the territory of Gaza reduced in any way. We won't support that," Kirby told reporters.

Kirby declined to outline any diplomatic conversations the U.S. has had with Israel about the matter, but emphasized that Washington has "been very clear and consistent, both in private and publicly, that we do not want to see the territory of Gaza reduced in any way."

Israel has since December been moving toward the establishment of its more than half-mile so-called "buffer zone" inside Gaza along the border with Israel, destroying buildings in the area to make way for the corridor.

On Tuesday, Israeli forces were ambushed while attempting to demolish two buildings in central Gaza's Maghazi refugee camp, killing 21 troops and injuring several more. Maghazi is located just across the border from Israel.

The attack is the single deadliest for Israeli forces since the war began in October. A rocket-propelled grenade fired by a Hamas fighter set off a chain reaction of Israeli mines, prematurely setting them off and collapsing the buildings with Israeli troops still inside.

Israeli Prime Minister Benjamin Netanyahu has elicited furor in Egypt after saying publicly that Israel wants to take control of the border area between Gaza and Egypt. Netanyahu said Saturday the 8.7-mile (14-kilometer) strip, which is known in Israel as the Philadelphi Corridor, "must be in our hands."

Diaa Rashwan, the chairman of Egypt's State Information Service (SIS), said Cairo would consider any attempt by Israel to occupy the area as a "violation of the security agreements and protocols signed between it (Israel) and Egypt."

"It must be strictly emphasized that any Israeli move in this direction will lead to a serious threat to Egyptian-Israeli relations," he added.

Nearly 25,500 Palestinians have been confirmed killed in Israel's attacks on the Gaza Strip since Oct. 7. Thousands more are feared dead under the rubble.

The vast majority of Palestinians who have been killed, an estimated two-thirds, are women and children.

The Israeli offensive has left 85% of Gaza's population internally displaced amid acute shortages of food, clean water and medicine, while 60% of the enclave's infrastructure has been damaged or destroyed, according to the U.N.