At least 22 children have been killed in Gaza after Israel hit the region with a wave of airstrikes, the Hamas-run health ministry said on Wednesday.

Israeli Prime Minister Benjamin Netanyahu said the strikes were targeting Hamas leader Mohammed Sinwar and promised an escalation of force.

The Israel Defense Forces said they hit an underground Hamas command centre beneath the European Hospital in Khan Younis in southern Gaza.

The strikes killed at least 60 people in total, Gaza’s Health Ministry reported, including almost 50 people around Jabaliya in northern Gaza and ten more in Khan Younis.

Officials said at least nine missiles fell in the courtyard facing the entrance to the hospital.

Hamas rejected any Israeli claims about Sinwar, saying in a statement: “The Palestinian resistance alone, through its official platforms, is the authority authorised to confirm or deny what is published.”

Sinwar became the militant group’s de facto leader after the Israeli military killed his brother, Yahya Sinwar, last October.

Israeli forces also struck the Nasser Medical Complex on Tuesday evening, killing two people, including well-known journalist Hassan Eslaih, and leaving several patients and staff wounded, according to local reports. Israel claims Eslaih was a Hamas operative.

Earlier in the week, Netanyahu said there is "no way" Israel would halt its war in Gaza, dimming hopes for a ceasefire.

Netanyahu told wounded soldiers the Israeli army was just days away from a promised escalation of force and would enter Gaza “with great strength".

His comments are likely to complicate talks on a new ceasefire that had seemed to gain momentum after Hamas released the last living American hostage on Monday in a gesture to US President Donald Trump, who is visiting the region - but skipping Israel.

Trump landed in Saudi Arabia yesterday, where he signed the "largest arms deal in history" with the country's de facto ruler, Crown Prince .

President Trump is using the first major foreign trip of his term to emphasise the promise of economic prosperity over instability in a region reeling from multiple wars.