— Israeli strikes destroyed the home of Hamas' leader in the Gaza Strip and killed 17 Palestinians on Sunday as the UN Security Council prepares to meet amid global alarm at the escalating conflict.

The heaviest fighting since 2014, sparked by unrest in Jerusalem, saw both sides again trade heavy fire, with the death toll rising to 174 in the crowded coastal enclave of Gaza and 10 in Israel since Monday.

Israel said on Sunday morning its "continuing wave of strikes" had in the past 24 hours struck over 90 targets across Gaza, where the destruction of a building housing news media organisations sparked international outcry.

In Gaza, emergency teams worked to pull out bodies from vast piles of smoking rubble and toppled buildings, as relatives wailed in horror and grief.

UN Secretary General Antonio Guterres was "dismayed" by civilian casualties in Gaza and "deeply disturbed" by Israel's strike on Saturday on the tower housing the Associated Press and Al Jazeera bureaus, a spokesperson said.

Israeli forces said on Sunday that about 2,900 rockets had been fired from the coastal strip controlled by Hamas towards Israel, "of which approximately 450 failed launches fell in the Gaza Strip".

Israel's Iron Dome anti-missile system had intercepted some 1,150 rockets in almost a week during which Israeli residential buildings have been hit and sirens have sounded across towns and major cities.

The bloodiest military conflict in seven years has also sparked a wave of inter-communal violence and mob attacks between Jews and Arab-Israelis, as well as deadly clashes in the occupied West Bank, where 15 Palestinians have been killed since Friday.

Israeli air strikes also hit the home of Yahya Sinwar, head of Hamas' political wing in the Gaza Strip, the army said, releasing a video showing plumes of smoke and intense damage, but without saying if he was killed.

Media offices destroyed 

The civilian death toll has mounted in Gaza, where at least 47 children have been killed, 1,200 people wounded and entire buildings and city blocks reduced to rubble.

One strike on Gaza killed 10 members of an extended family.

The children "didn't carry weapons, they didn't fire rockets", said Mohammad Al Hadidi, one of the grieving fathers.

Some 10,000 Gazans have fled their homes near the Israeli border for fear of a ground offensive, the UN said.

"They are sheltering in schools, mosques and other places during a global Covid-19 pandemic with limited access to water, food, hygiene and health services," UN humanitarian official Lynn Hastings said.

Balls of flame and a cloud of debris shot into the sky Saturday afternoon as Israel's air force flattened the 13-floor Gaza building housing Qatar-based Al Jazeera and the Associated Press news agency, after giving a warning to evacuate.

Al Jazeera's Jerusalem bureau chief, Walid Al Omari, told AFP: "It is clear that those who are waging this war do not only want to spread destruction and death in Gaza, but also to silence media that are witnessing, documenting and reporting the truth."

AP President and CEO Gary Pruitt said he was "shocked and horrified" by the attack.

AFP Chairman Fabrice Fries said the agency "stands in solidarity with all the media whose offices were destroyed in Gaza" and called on all parties "to respect the media's freedom to report on events".

'Grave concern' 

The UN Security Council was due to meet at 14:00 GMT Sunday.

Israel ally Washington, which had blocked a UNSC meeting scheduled for Friday, has been criticised for not doing enough to stem the bloodshed.

US President Joe Biden again underscored Israel's right to defend itself in a phone call with Israeli Prime Minister Benjamin Netanyahu.

Biden also expressed his "grave concern" over the violence as well as for the safety of journalists.

Earlier Saturday, Biden also spoke to Palestinian president Mahmud Abbas in their first call since the US president took office.

US Secretary for Israel-Palestinian Affairs Hady Amr was to hold talks on Sunday with Israeli leaders before meeting Palestinian officials to seek a "sustainable calm", the State Department said.

European Union foreign ministers will also hold talks on Tuesday on how to "end the current violence," foreign policy chief Josep Borrell said.

'They're striking our children' 

In Gaza, the grieving father Hadidi said he had lost most of his family in a strike on a three-storey building in the Shati refugee camp that killed 10 relatives - two mothers and their four children each.

"They are striking our children - children - without prior warning," said the devastated father, whose five-month-old baby was also wounded in the explosion.

Palestinian militants responded with volleys of rockets into Israel, killing a man on the outskirts of commercial capital Tel Aviv, police and medics said.

The escalating conflict was sparked by unrest in Jerusalem that had simmered for weeks and led to clashes between riot police and Palestinians, fuelled by anger over planned Israeli expulsions of Palestinians in the Sheikh Jarrah neighbourhood of east Jerusalem.

Major clashes broke out at the Al Aqsa Mosque compound -- Islam's third-holiest site -- on May 7 following a crackdown against protests.

Mixed Jewish-Arab towns within Israel have also seen mob violence, with more than 750 people arrested this week, police said.