Israeli air strikes killed 21 people in Gaza on Monday, raising the overall death toll to 98 on the sixth day of the relentless bombing campaign.

In the latest raids, one person was killed when Israeli warplanes hit the Shuruq tower media centre in Gaza City, which houses Palestinian and international media outlets, among them official Hamas broadcaster Al-Aqsa TV.

It was the second time the building had been hit in as many days and left another three people injured, the Hamas-run ambulance service said.

Elsewhere, two more people died in bombing in Nusseirat refugee camp in central Gaza, medics said.

There was no immediate information on the identities of any of the victims.

Also during the afternoon, one person was killed and another two wounded when a missile struck a car just north of Gaza City, medics said. There were no immediate details on identity of the victims.

Medics also said 22-year-old Ramadan Mahmud died of injuries suffered in Maghazi refugee camp in central Gaza on Sunday.

Another three people also succumbed to injuries sustained in the violence, but the health ministry could not immediately provide details on their identities.

Elsewhere, a missile hit a motorcycle east of Khan Yunis in southern Gaza, killing two men and critically wounding a child who was with them, Gaza's ambulance service said.

The two were named as Abdullah Abu Khater, 30, and Mahmud Abu Khater, 32.

An earlier strike on Qarara in the same area killed two farmers, Ibrahim al-Astal and Obama al-Astal, medics said.

In a strike on southern Gaza City, a car was hit, killing one man and injuring another three, officials said, naming him as 23-year-old Mohammed Shamalah.

Shortly before that, three people were killed in a strike on a car in Deir al-Balah in central Gaza, all of them from the same family: Amir Bashir, Tamal Bashir and Salah Bashir.

Early in the day, two women and a child were among four killed in a strike on Gaza City's eastern Zeitun neighbourhood -- Nisma Abu Zorr, 23, Mohammed Abu Zorr, five, Saha Abu Zorr, 20 and Ahid al-Qatati, 35.

And medics said another man had been found dead in the northern town of Beit Lahiya, naming him as Abdel Rahman al-Atar, a 50-year-old farmer.

Gazans search desperately for safe place under fire

Every time six-year-old Mohammed hears the sound of Israeli missiles landing near his home in Gaza City, he turns to his mother and asks: "When are we going to die?"

Traumatised by the bombardment, and terrified for their children, his family has decided to leave Gaza City, which has borne the brunt of relentless Israeli air strikes for six straight days.

So they upped and moved to Khan Yunis in southern Gaza, which has been less affected by the violence.

But they know that nowhere in Gaza is safe. No corner of this tiny coastal strip has been left untouched. Every major urban centre in the territory of some 1.6 million residents has been bombarded.

There are no bomb shelters for residents, leaving each family to find the safest place in their home to cling to when the warplanes arrive.

Mohammed's family hope Khan Yunis might prove slightly safer, and are staying there with his mother's relatives.

"My children are terrified," says his mother Umm Jihad, 37.

"My son Mohammed refuses to eat. He follows me everywhere because he's so scared and asks me every 10 minutes when we're going to die.

"He says he won't go back to school because he's scared he'll be martyred or that he'll come back from school and find that I or his brothers have been killed," she says.

Their home is on the ninth floor of an apartment building in the western sector of Gaza City.

"The strikes would shake the whole building, and eventually they blew out the windows and knocked down the door. That was when we decided to go Khan Yunis," says Umm Jihad, speaking to AFP on the phone.

Khan Yunis has also been hit in the conflict, but less so than Gaza City and the family feels better protected.

"The fear and anxiety have followed me here though," she says. "I don't know what to say to my children and how they will overcome this fear when the war is over."

Walid Sultan, 30, fled his home in the northern town of Beit Lahiya along with his pregnant wife, their daughter and dozens of their neighbours after their district, which is close to the border with Israel, came under heavy fire.

He came to Gaza City to take refuge with a friend in the Sheikh Radwan neighbourhood, but has found no peace there either.

"We fled death, but it is waiting for us at every corner," he says.

"I left my home in Salateen because I was scared the Israelis would launch a ground invasion. Last time they did that, their tanks came to our area and destroyed my home.

"The situation is terrible here, too. I feel helpless because I can't protect my family," he adds.

"I feel the fear of my daughter, who has panic attacks and screams at the sound of the shelling. My wife is in the final months of her pregnancy, but where can we go?"

Suhaila Nouri, 43, decided to leave after an awful night when she was convinced she would die.

"It was a terrible night. The explosions were so loud it sounded like they were inside my house," she says. "I just sat there and waited to die."

In the morning she discovered shrapnel and debris all over the garden of her Beit Lahiya home and decided to move to Gaza City, to stay with her brother.

The city is under attack constantly from the air, but as a resident of the border area, Nouri decided it would be safer to move in case Israel launches a ground invasion.

Maysa Shanti, 40, left her home in northwestern Gaza City with her family, and moved into her relatives' house in the city's upscale Rimal neighbourhood.

"There was heavy Israeli bombing of a resistance training site behind my apartment. It shattered the windows of my house and I decided to leave for somewhere safer because I was afraid for my family and the kids were panicking," she says.

The days and nights of bombing have left the family bleary-eyed and exhausted, desperate for a chance to sleep.

"But we can't sleep here either," Shanti says.

"The sound of explosions is continuous here as well. All we can do is try to comfort each other."

Italy, Qatar urge immediate ceasefire in Gaza

Italian Prime Minister Mario Monti and his Qatari counterpart urged an immediate ceasefire in Gaza on Monday.

"We are very worried about the escalating violence," Monti said at a joint news conference in Doha with Qatari Prime Minister Sheikh Hamad bin Jassem al-Thani.

"A ceasefire must quickly be reached to allow the peace process to begin as soon as possible," he told reporters according to an official translation.

The Qatari prime minister described the events in the Gaza Strip as "unacceptable" and echoed his counterpart by calling both sides to commit to a ceasefire.

"We are for a return of calm. But this must happen clearly and no side must be allowed to continue to assassinate or initiate side battles," said Sheikh Hamad. "A truce must be observed from both sides."

As fighting continued on Monday, ceasefire efforts gathered steam, with senior Hamas officials in Cairo saying Egyptian-led talks on Sunday with Israel were "positive" but now focused on the need to guarantee the terms of any truce.

Monti said his government was in contact with "Egyptian President Mohamed Morsi, Israeli Prime Minister Benjamin Netanyahu, the Palestinian Authority, as well as Qatar's emir and its prime minister".

The Qatari premier also called for "lifting the oppressive blockade on Gaza."

In October, Qatar's emir was the first head of state to visit Gaza since the Palestinian group Hamas seized it from forces loyal to Palestinian President Mahmud Abbas in 2007.