Israeli troops carried out building-by-building searches at Gaza's main hospital on Friday, after a communications blackout in the Palestinian territory compounded fears for civilians trapped inside the facility.

Al-Shifa hospital has become a focal point for Israeli operations in northern Gaza since soldiers raided the complex on Wednesday, hunting for a command centre they say militant group Hamas operates at the site.

Hamas and hospital managers deny that charge, and there has been international concern about thousands of people -- including wounded patients and premature babies -- believed to be inside.

Israel has vowed to "crush" Hamas in response to the group's October 7 attack, which killed 1,200 people, most of them civilians, and saw about 240 taken hostage, according to Israeli officials.

The army's aerial bombing and ground campaign has killed 11,500 people, including thousands of children, according to Gaza's Hamas government.

AFPTV live camera footage showed plumes of thick smoke rising over the north of the narrow coastal territory on Friday.

Israel has defended the operation, and the military said it found rifles, ammunition, explosives and the entrance to a tunnel shaft at Al-Shifa.

Israeli Prime Minister Benjamin Netanyahu alleged hostages may even have been held at the medical facility.

"We had strong indications that they were held in the Shifa Hospital, which is one of the reasons we entered the hospital," he told "CBS Evening News".

"If they were (there), they were taken out," he said.

Communications blackout 

Communications with Gaza were severed once again, with network provider Paltel saying it was because "all energy sources sustaining the network have been depleted, and fuel was not allowed in".

The United Nations warned the outage would compound the misery of civilians, complicating efforts to distribute desperately needed aid and possibly triggering looting of its supplies.

"When you have a blackout and you cannot communicate with anyone anymore... that triggers and fuels even more the anxiety and the panic," said Philippe Lazzarini, head of the UN agency for Palestinian refugees (UNRWA).

The UN agency said no aid trucks entered Gaza from Egypt for a second consecutive day and that it would be unable to manage or coordinate more convoys due to the lack of communications.

Israel said its forces were searching Al-Shifa "one building at a time".

The army said it struck numerous "terror targets" in Gaza overnight Thursday-Friday, locating rockets and unmanned aerial vehicles at a post of the Islamic Jihad militant group in the north of the territory.

It said troops killed Hamas members at a school where they found a "large number of weapons".

The military also said troops had recovered the remains of kidnapped woman soldier Noa Marciano, 19, "from a structure adjacent to Al-Shifa hospital".

It had confirmed her death this week, without giving the cause. Hamas said she had been killed in Israeli bombing.

On Thursday the army said soldiers near Al-Shifa found the body of another hostage. Yehudit Weiss, 65, had been kidnapped from the border kibbutz community of Beeri.

'Pleading for a sip' 

The Israeli government has come under increasing pressure to back up its allegations that Hamas is using hospitals as command centres.

The United States has stood behind its ally, however, with President Joe Biden this week saying he had asked Israel to be "incredibly careful" in its military moves around Gaza hospitals.

Palestinian health officials on Thursday said the Al-Ahli hospital had come under attack. The Palestinian Red Crescent reported that medical staff were unable to reach casualties in the courtyard because of explosions and gunfire.

More than half of Gaza's hospitals are no longer functional, due to either combat, damage, or shortages, and Israel's raid on Al-Shifa left extensive damage to the radiology, burns and dialysis unit, the Hamas-run health ministry said.

AFPTV video showed Palestinians paying their last respects to loved ones on Friday as around a dozen bodies shrouded in white were laid out in front of the Indonesian hospital at Beit Lahia in north Gaza.

On Thursday, Jews and Arabs had come together for the funeral of another casualty of the Beeri attack -- peace activist Vivian Silver, who was hailed as an "extraordinary woman".

Negotiations are ongoing for the release of the hostages, including children, in exchange for a pause in fighting.

Qatar, where Hamas has political offices, and Egypt have been mediating what Egypt's foreign minister has described as "very delicate" discussions.

"We are hopeful that our efforts and the efforts of others will bring about the speedy release," Sameh Shoukry said.

On the ground, conditions are rapidly deteriorating for Palestinian civilians, the UN warned.

More than 1.5 million people have been internally displaced, and Israel's blockade of the territory means "civilians are facing the immediate possibility of starvation," World Food Programme head Cindy McCain said.

Food and water have become "practically non-existent," the WHO added.

Lazzarini described children sheltering at a UN school "pleading for a sip of water, or for a loaf of bread".

West Bank flare-up

Israel's ground operation has so far focused on north Gaza, where it has announced the seizure of the parliament building, government offices, Hamas police headquarters and a key port. It says 51 of its troops have been killed.

Alongside the war in Gaza, there is growing concern about violence in the Israeli-occupied West Bank, where violence by Israeli settlers against Palestinians has surged.

Raids by Israel's military, which says it is responding to "a significant rise in terrorist attacks", have also multiplied in the West Bank where the Palestinian death toll has soared.

The Israeli army said on Friday it had killed "at least five terrorists" at Jenin refugee camp in the West Bank.

Overnight, AFP journalists had reported a large deployment of Israeli troops triggered clashes at the camp. Hamas said three of its fighters were killed.

US Secretary of State Antony Blinken has urged Israel to take "urgent" action to "de-escalate tensions in the West Bank, including by confronting rising levels of settler extremist violence," the State Department said.

Elsewhere, Israeli air strikes killed two pro-Iranian fighters near the Syrian capital Damascus early on Friday during raids targeting a Hezbollah arms depot and other sites near Syria's capital, a war monitor said.

The group of independent global leaders known as The Elders called on Biden to embrace a "historic opportunity" and deliver a peace plan between the Israelis and Palestinians.

"As polarisation increases, the world needs you to set out a vision for peace," they said in an open letter, stressing the plan "must recognise the equal rights of Palestinians and Israelis."