United States President Joe Biden told Israel's Prime Minister Benjamin Netanyahu that he expects “significant de-escalation” on Wednesday in the violence with the Palestinians, amid intense efforts to reach a ceasefire.

Deafening air strikes and rocket fire once more shook Gaza in the violence that has since May 10 claimed 219 Palestinian lives according to the Gaza health ministry and killed 12 people in Israel according to Israeli police.

“The president conveyed to the prime minister that he expected a significant de-escalation today on the path to a ceasefire,” the White House said after a fourth phone call in a little over a week.

As diplomatic efforts intensified to stem the bloodshed, Germany said its top diplomat was heading to Israel for talks on Thursday.

Netanyahu earlier on Wednesday issued a tough threat against the Gaza Strip's rulers Hamas, who Israel says has fired around 3,700 rockets at Israel since May 10.

“You can either conquer them, and that's always an open possibility, or you can deter them, and we are engaged right now in forceful deterrence,” he told foreign ambassadors.

“But I have to say we don't rule out anything.”

But an Israeli military official, speaking on condition of anonymity, said in a separate briefing that Israel was assessing at what stage it may stop its military campaign.

“We are looking at when is the right moment for a ceasefire,” said the source.

Israel was evaluating whether its objective of degrading Hamas' capabilities had been achieved, the military source said, and “whether Hamas understands the message” that its rocket barrages towards Israel cannot recur.

Warplanes hit Gaza City again in the pre-dawn hours, as the Israeli military kept targeting fighters and infrastructure in the crowded enclave which has been under Israeli blockade for nearly 15 years.

Read: A timeline of Israel's latest military offensive in Gaza

Gaza mother-of-seven Randa Abu Sultan, 45, recounted how her family crowded into one room to sit out another night of fear.

“We're all terrified by the sound of explosions, missiles and fighter jets,” she said. “My four-year-old son tells me he's scared that if he falls asleep, he'll wake up to find us dead.”

Diplomatic flurry

The United States, a key Israel ally, has repeatedly blocked the adoption of a joint United Nations Security Council statement calling for a halt to violence.

A UN Security Council meeting broke up without issuing a statement late on Tuesday, but France then said it had proposed a resolution calling for a ceasefire, in coordination with Egypt and Jordan.

Beijing's ambassador to the UN, Zhang Jun, told reporters his team had heard the French ceasefire proposal and China was “supportive”.

But the United States said on Wednesday it would not support the proposed resolution, saying it could undermine efforts to de-escalate the crisis.

“We've been clear and consistent that we are focused on intensive diplomatic efforts underway to bring an end to the violence and that we will not support actions that we believe undermine efforts to de-escalate,” a US spokesperson at the UN told AFP.

German Foreign Minister Heiko Maas was to meet Israel's foreign and defence ministers on Thursday and travel to Ramallah to hold talks with the Palestinian premier, his office said.

Humanitarian crisis

Israeli air strikes have killed at least 219 people in Gaza, including 63 children, and wounded 1,530, according to health ministry figures.

Meanwhile, Hamas has launched around 3,700 rockets at Israel since May 10.

Palestinian rocket fire has killed 12 people in Israel, including two children, one Indian and two Thai nationals, and injured 333, Israeli authorities said.

Overnight, armed groups fired 50 rockets towards southern Israel, 10 of which fell short and struck inside Gaza, the Israeli military said.

The Israeli army meanwhile said it had attacked “40 underground Hamas targets” overnight in southern Gaza.

In the enclave's north, a journalist working for Hamas-linked Al-Aqsa radio was killed when an Israeli strike hit his home, authorities said.

Israel's bombing campaign has also left Gaza's two million population desperate for relief.

Hospitals have been overwhelmed by patients, there are frequent blackouts and sewage from broken pipes has flooded some areas.

Some 72,000 civilians have fled their homes, seeking refuge in UN-run schools and other public buildings, the United Nations says.

'Day of anger'

The latest violence was sparked after clashes broke out at East Jerusalem's flashpoint Al-Aqsa mosque compound, one of Islam's holiest sites.

This followed violence over the forced evictions of Palestinian families from homes in Jerusalem's Sheikh Jarrah district.

Palestinians clashed with police in multiple towns and in annexed east Jerusalem on Tuesday after Palestinian president Mahmud Abbas's Fatah movement had called for a “day of anger”.

The Palestinian health ministry said a Palestinian woman was shot dead on Wednesday near Hebron, as the army said she had tried to attack Israeli forces.

The death brought to 25 the number of Palestinians killed in the West Bank since May 10.

In northern Israel, the army said it fired artillery shells toward southern Lebanon, in response four rockets launched at the Jewish state from Lebanese territory, in the third such attack in less than a week.