Israel killed one of Hamas’s top leaders in Gaza, interior minister Said Siam, the most senior leader to have been killed in the 20-day-old war in the enclave, as U.N. chief Ban Ki-moon led international protests describing the Palestinian death toll as "unbearable".

"Leader Said Siam, his son and his brother fell as martyrs in Gaza," reported Al-Quds television, based in Beirut.

The three died in an Israeli air strike on the house of Siam’s brother north of Gaza City.

Siam was in charge of 13,000 police and security men, many of whom are actively involved in fighting Israel. He founded the Executive Force, a Hamas security branch originally set up to rival Palestinian President Mahmoud Abbas’s presidential guard.

U.N. Chief Condemnation

U.N. chief Ban Ki-moon led international protests Thursday describing the Palestinian death toll as "unbearable" as Israeli air strikes hit a hospital, media building and UN compound.

He also said the death toll from the war, now nearing 1,100, has become "unbearable."

"I have conveyed my strong protest and outrage and demanded a full explanation from the defense minister and foreign minister," Ban told reporters in Tel Aviv after the strike on a UN compound in Gaza.

The U.N. suspended its operations in Gaza after Israeli shells smashed into the compound, setting fire to warehouses holding badly-needed aid.

A building housing the offices of several media organizations, a hospital wing and the United Nations headquarters in Gaza City were struck by Israeli forces Thursday, Al Arabiya TV and witnesses reported, prompting the U.N. to suspend operations.

Three Israeli tank shells smashed into UNRWA, the U.N.’s main relief agency in Gaza, wounding three workers, the pan-Arab news station reported, in an attack condemned by the U.N. chief.

The Israeli airstrike on the al-Shorouk media building killed two Abu Dhabi TV journalists and wounded several others, Al Arabiya TV reported.

A wing of a-Quds Hospital in Gaza City caught fire after another Israeli strike, witnesses said, though it was not immediately clear whether there were injuries.

Al Arabiya TV reported that the Israeli tanks encircled the house of Hamas leader Mahmoud al-Zahaar in Gaza City. Palestinian fighters said a number of Israeli soldiers were injured in a military unit in west Gaza, Al Arabiya said.

UNWRA spokesman Adnan Abu Hasna told AFP it was suspending all operations because of the shelling.

One of the buildings, containing "hundreds of tons" of humanitarian aid, was on fire, while other parts of the compound sustained shrapnel damage, another UNRWA official told AFP, speaking on condition of anonymity.

Earlier, the compound was damaged when another Israeli shell landed next to the building, which is near the Islamic University in the centre of Gaza City,

Chris Gunness, a Jerusalem-based spokesman for the agency, said hundreds people were taking refuge inside the compound when it was hit.
 
Media Offices Hit

The tower block in the city-center houses several international media outlets including Reuters, Fox and Sky news, and the coordinates were provided to the Israeli army at the start of the war, Nidal Hassan, head of Al Arabiya’s Ramallah office, told AlArabiya.net.

“They (Israeli army) have coordinates of everything – official and unofficial buildings. This was definitely planned, this was not a mistake,” he said.

Hassan said he spoke with Al Arabiya journalists who were in the building. They reported that it was hit by two or three tanks at around 11:15 a.m. Two Abu Dhabi TV journalists were injured, not killed as initial reports said, and transported to Shifaa hospital.

Reuters journalists said they did not see any armed men in the building prior and said the Israeli army had assured them “on several occasions that it was not a target” and had spoken with Reuters staff in Jerusalem shortly before the explosion to check the location of the Reuters bureau in Gaza.

An army spokeswoman said after the blast that she was checking into what happened. She said troops were engaged with Hamas fighters in exchanges of fire in the city and said fighters had taken over a media office in the same area late on Wednesday.
 
Hospital Attack

Battles raged throughout the embattled territory as tanks advanced into the heart of the Tal Al-Hawa neighborhood, where the hospital is located and hundreds of people had taken shelter from advancing Israeli tanks in the early morning hours, sending hundreds of terrified civilians fleeing.

Hamas gunmen fired at the advancing troops with anti-tank rockets and mortars and thick columns of black smoke rose into the sky above Gaza City in the south, east and north.

A woman and her three children were killed in Beit Lahiya, though the exact number of casualties was not immediately clear as the clashes blocked ambulances from reaching the wounded, medics said.
 
Dozens of families had been sheltered inside al-Quds Hospital in Tal al-Hawa after tanks rumbled in after dawn.

"I brought the children to the hospital because they were scared at home, but here they are even more terrified," 40-year-old Hossein said as he huddled with his wife and five children in the pediatric ward.

"We can’t take this any longer. Look at my children, they’re trembling," he said as explosions ripped through the air like thunderclaps and Israeli troops and Hamas fighters clashes less than 300 meters (yards) away.

Israeli warplanes pummeled the densely-populated territory with some 70 strikes overnight, targeting Palestinian fighters, rocket launching sites and weapon storage sites, including a mosque in the south, the army said.

Fighters in Gaza fired 17 rockets and mortars into Israel in the space of several hours in the morning, it said.

The Palestinian death toll from Israel’s air-and-ground offensive has risen to at least 1,067, according to the Hamas-run Health Ministry in Gaza, and there were more than 5,000 wounded.

(Text and References: Alarabiya.net and Agencies)