The top US diplomat met Saudi Arabia’s de-facto ruler on Monday during a Middle East visit Palestinians hope will clinch a truce before a threatened Israeli assault on Rafah, a border city where about half the Gaza Strip population is sheltering.

Secretary of State Antony Blinken arrived in Riyadh at the start of his first trip to the region since Washington brokered an offer, with Israeli input, for the first extended ceasefire of the war.

Blinken’s meeting with Saudi Crown Prince Mohammed bin Salman lasted about two hours.

State Department spokesperson Matthew Miller said Blinken and the crown prince had discussed regional coordination to achieve “an enduring end” to the crisis. “The Secretary underscored the importance of addressing humanitarian needs in Gaza and preventing further spread of the conflict,” Miller said in a statement.

Blinken did not answer reporters’ questions as he returned to his hotel.

The ceasefire offer, delivered to Hamas last week by Qatari and Egyptian mediators, awaits a reply from militants who say they want more guarantees it will bring an end to the four-month-old war.

“Impossible to say if we’ll get a breakthrough, when we’ll get a breakthrough,” a senior US official told reporters during the flight to the Saudi capital. “The ball right now is in Hamas’ court.”

Blinken also aims to win backing for US plans for what would follow a truce: rebuilding and running Gaza, and ultimately for a Palestinian state - which Israel now rejects - and for Arab countries to normalize ties with Israel.

Washington also seeks to prevent further escalation elsewhere in the Middle East, after days of US airstrikes against pro-Iranian armed groups across the region.

Miller said Blinken and the crown prince had discussed the urgent need to reduce regional tensions.

In London, British defence minister Grant Shapps told parliament that the air strikes had depleted the ability of Yemen’s Houthis to target Red Sea shipping but the threat was “not fully diminished.”

‘Total victory’

Israel threatened a new ground assault on Rafah, a small city on the southern border with Egypt where over half of Gaza’s 2.3 million people are now living, mostly in makeshift tents.

Israeli Prime Minister Benjamin Netanyahu, visiting troops on Monday, said Israeli forces had killed or wounded more than half of Hamas’ fighting forces and would carry on until “total victory”.

Senior Hamas official Sami Abu Zuhri dismissed Netanyahu as “playing the game of making delusional victories” in the face of continued resistance.

The ceasefire proposal, as described by sources close to the talks, envisions a truce of at least 40 days when militants would free civilians among remaining hostages they are holding, followed by later phases to hand over soldiers and bodies.

The only truce so far lasted a week in November.

“We want the war to end and we want to go back home, this is all that we want at this stage,” said Yamen Hamad, 35, a father of four reached by messaging app at a U.N. school in Deir al-Balah in central Gaza. The area is one of the few where Israeli tanks have yet to advance, and is jammed with tens of thousands of displaced families.

“All we do is listen to the news through small radios and view the internet looking for hope. We hope that Blinken will tell Netanyahu enough is enough, and we hope our factions decide in the best interest of our people.”

Fighting in Khan Younis, Gaza city

Israeli tanks have been advancing for two weeks in Khan Younis. Fighting has also resurged in Gaza City in the north of the strip, in areas Israel said it subdued in the war’s first two months.

The Israeli military said on Monday its forces had killed dozens of Palestinian fighters in northern, central and southern Gaza over the last 24 hours.

As night fell, Khan Younis residents said Israeli tanks had stepped up shelling around Nasser Hospital, the largest functioning medical facility in the south, setting some houses ablaze.

The Palestinian Red Crescent Society said some 8,000 displaced people had been evacuated from its headquarters in Khan Younis and Al-Amal hospital after two weeks surrounded by Israeli troops.

At the hospital, only 40 elderly individuals, around 80 patients and 100 administrative and medical staff remained.

Palestinians described heavy fighting in Gaza City, particularly in areas close to the Mediterranean shore under bombardment from Israeli warships. UNRWA, the UN aid agency for Palestinians, said a food convoy headed there had come under fire although nobody was hurt.

UNRWA, a source of critical aid, has said it may be forced to shut down operations across the region this month after donors withdrew funding over Israeli allegations some of its staff were involved in the 7 Oct attack by Hamas militants that precipitated the war. UNRWA says it acted swiftly to fire staff after being alerted of Israel’s allegations.

UN Secretary-General Antonio Guterres on Monday said he had appointed former French Foreign Minister Catherine Colonna to lead an independent review into the allegations.

Gaza authorities say more than 27,000 Palestinians have been confirmed killed in Israel’s assault, with thousands more feared unrecovered in the rubble. Israel says 226 of its soldiers have been killed in its offensive, launched after 1,200 people were killed and 253 hostages captured on 7 Oct.

The Gaza war has stoked violence in the Israeli-occupied West Bank, where Palestinians also seek statehood. On Monday, Israeli police said officers killed a knife-wielding male who tried to attack them near Maale Adumim, a large West Bank settlement. The official Palestinian news agency WAFA said a 14-year-old Palestinian was killed in the incident.